diff --git a/src/builder/bundle_proposer.rs b/src/builder/bundle_proposer.rs
index 222080d43..53c30308a 100644
--- a/src/builder/bundle_proposer.rs
+++ b/src/builder/bundle_proposer.rs
@@ -117,7 +117,18 @@ where
         )?;
 
         // Limit the amount of gas in the bundle
-        let ops = self.limit_gas_in_bundle(ops);
+        tracing::info!(
+            "Builder id: {}, starting bundle proposal with {} ops",
+            self.id,
+            ops.len(),
+        );
+        let (ops, gas_limit) = self.limit_gas_in_bundle(ops);
+        tracing::info!(
+            "Builder id: {}, bundle proposal after limit had {} ops and {:?} gas limit",
+            self.id,
+            ops.len(),
+            gas_limit
+        );
 
         // Determine fees required for ops to be included in a bundle, and filter out ops that don't
         // meet the requirements. Simulate unfiltered ops.
@@ -174,6 +185,12 @@ where
                 expected_storage.merge(&op.simulation.expected_storage)?;
             }
             if let Some(gas_estimate) = gas_estimate {
+                tracing::info!(
+                    "Builder id: {}, bundle proposal succeeded with {} ops and {:?} gas limit",
+                    self.id,
+                    context.iter_ops().count(),
+                    gas_estimate
+                );
                 return Ok(Bundle {
                     ops_per_aggregator: context.to_ops_per_aggregator(),
                     gas_estimate,
@@ -309,7 +326,7 @@ where
                 };
                 let max_cost = op.max_gas_cost();
                 if *balance < max_cost {
-                    info!("Rejected paymaster {paymaster:?} becauase its balance {balance:?} was too low.");
+                    info!("Rejected paymaster {paymaster:?} because its balance {balance:?} was too low.");
                     paymasters_to_reject.push(paymaster);
                     continue;
                 } else {
@@ -505,7 +522,7 @@ where
         Ok(())
     }
 
-    fn limit_gas_in_bundle(&self, ops: Vec<OpFromPool>) -> Vec<OpFromPool> {
+    fn limit_gas_in_bundle(&self, ops: Vec<OpFromPool>) -> (Vec<OpFromPool>, u64) {
         let mut gas_left = U256::from(self.settings.max_bundle_gas);
         let mut ops_in_bundle = Vec::new();
         for op in ops {
@@ -516,7 +533,10 @@ where
             gas_left -= gas;
             ops_in_bundle.push(op);
         }
-        ops_in_bundle
+        (
+            ops_in_bundle,
+            self.settings.max_bundle_gas - gas_left.as_u64(),
+        )
     }
 
     fn emit(&self, event: BuilderEvent) {
diff --git a/src/builder/bundle_sender.rs b/src/builder/bundle_sender.rs
index 02bc8aaf2..22a383562 100644
--- a/src/builder/bundle_sender.rs
+++ b/src/builder/bundle_sender.rs
@@ -26,7 +26,6 @@ use crate::{
         block_watcher,
         emit::WithEntryPoint,
         gas::GasFees,
-        math,
         protos::op_pool::{
             self, op_pool_client::OpPoolClient, RemoveEntitiesRequest, RemoveOpsRequest,
         },
@@ -34,9 +33,6 @@ use crate::{
     },
 };
 
-// Overhead on gas estimates to account for inaccuracies.
-const GAS_ESTIMATE_OVERHEAD_PERCENT: u64 = 10;
-
 #[derive(Debug)]
 pub struct Settings {
     pub replacement_fee_percent_increase: u64,
@@ -414,12 +410,11 @@ where
             bundle.rejected_ops.len(),
             bundle.rejected_entities.len()
         );
-        let gas = math::increase_by_percent(bundle.gas_estimate, GAS_ESTIMATE_OVERHEAD_PERCENT);
         let op_hashes: Vec<_> = bundle.iter_ops().map(|op| self.op_hash(op)).collect();
         let mut tx = self.entry_point.get_send_bundle_transaction(
             bundle.ops_per_aggregator,
             self.beneficiary,
-            gas,
+            bundle.gas_estimate,
             bundle.gas_fees,
         );
         tx.set_nonce(nonce);
diff --git a/src/op_pool/mempool/mod.rs b/src/op_pool/mempool/mod.rs
index 790f671ba..e0151f388 100644
--- a/src/op_pool/mempool/mod.rs
+++ b/src/op_pool/mempool/mod.rs
@@ -47,7 +47,7 @@ pub trait Mempool: Send + Sync {
     /// the specified maximum number of operations.
     ///
     /// NOTE: Will only return one operation per sender.
-    fn best_operations(&self, max: usize) -> Vec<Arc<PoolOperation>>;
+    fn best_operations(&self, max: usize, builder_id: u64) -> Vec<Arc<PoolOperation>>;
 
     /// Returns the all operations from the pool up to a max size
     fn all_operations(&self, max: usize) -> Vec<Arc<PoolOperation>>;
diff --git a/src/op_pool/mempool/uo_pool.rs b/src/op_pool/mempool/uo_pool.rs
index 224b1b3e2..b0156514f 100644
--- a/src/op_pool/mempool/uo_pool.rs
+++ b/src/op_pool/mempool/uo_pool.rs
@@ -3,7 +3,7 @@ use std::{
     sync::Arc,
 };
 
-use ethers::types::{Address, H256};
+use ethers::types::{Address, H256, U256};
 use itertools::Itertools;
 use parking_lot::RwLock;
 use tokio::sync::broadcast;
@@ -38,6 +38,7 @@ pub struct UoPool<R: ReputationManager> {
     reputation: Arc<R>,
     state: RwLock<UoPoolState>,
     event_sender: broadcast::Sender<WithEntryPoint<OpPoolEvent>>,
+    num_builders: u64,
 }
 
 struct UoPoolState {
@@ -54,6 +55,7 @@ where
         args: PoolConfig,
         reputation: Arc<R>,
         event_sender: broadcast::Sender<WithEntryPoint<OpPoolEvent>>,
+        num_builders: u64,
     ) -> Self {
         Self {
             entry_point: args.entry_point,
@@ -65,6 +67,7 @@ where
                 block_number: 0,
             }),
             event_sender,
+            num_builders,
         }
     }
 
@@ -319,7 +322,7 @@ where
         UoPoolMetrics::increment_removed_entities(self.entry_point);
     }
 
-    fn best_operations(&self, max: usize) -> Vec<Arc<PoolOperation>> {
+    fn best_operations(&self, max: usize, builder_id: u64) -> Vec<Arc<PoolOperation>> {
         // get the best operations from the pool
         let ordered_ops = self.state.read().pool.best_operations();
         // keep track of senders to avoid sending multiple ops from the same sender
@@ -327,6 +330,13 @@ where
 
         ordered_ops
             .into_iter()
+            .filter(|op| {
+                (self.num_builders == 1)
+                    | (U256::from_little_endian(op.uo.sender.as_bytes())
+                        .div_mod(self.num_builders.into())
+                        .1
+                        == builder_id.into())
+            })
             .filter(|op| {
                 // filter out ops from senders we've already seen
                 senders.insert(op.uo.sender)
@@ -391,9 +401,9 @@ mod tests {
         let hash = pool
             .add_operation(OperationOrigin::Local, op.clone())
             .unwrap();
-        check_ops(pool.best_operations(1), vec![op]);
+        check_ops(pool.best_operations(1, 0), vec![op]);
         pool.remove_operations(&vec![hash]);
-        assert_eq!(pool.best_operations(1), vec![]);
+        assert_eq!(pool.best_operations(1, 0), vec![]);
     }
 
     #[test]
@@ -406,9 +416,9 @@ mod tests {
         ];
         let res = pool.add_operations(OperationOrigin::Local, ops.clone());
         let hashes: Vec<H256> = res.into_iter().map(|r| r.unwrap()).collect();
-        check_ops(pool.best_operations(3), ops);
+        check_ops(pool.best_operations(3, 0), ops);
         pool.remove_operations(&hashes);
-        assert_eq!(pool.best_operations(3), vec![]);
+        assert_eq!(pool.best_operations(3, 0), vec![]);
     }
 
     #[test]
@@ -420,9 +430,9 @@ mod tests {
             create_op(Address::random(), 0, 1),
         ];
         pool.add_operations(OperationOrigin::Local, ops.clone());
-        check_ops(pool.best_operations(3), ops);
+        check_ops(pool.best_operations(3, 0), ops);
         pool.clear();
-        assert_eq!(pool.best_operations(3), vec![]);
+        assert_eq!(pool.best_operations(3, 0), vec![]);
     }
 
     #[test]
@@ -434,7 +444,7 @@ mod tests {
             create_op(Address::random(), 0, 1),
         ];
         pool.add_operations(OperationOrigin::Local, ops.clone());
-        check_ops(pool.best_operations(3), ops.clone());
+        check_ops(pool.best_operations(3, 0), ops.clone());
 
         pool.on_chain_update(&ChainUpdate {
             latest_block_number: 1,
@@ -450,7 +460,7 @@ mod tests {
             unmined_ops: vec![],
         });
 
-        check_ops(pool.best_operations(3), ops[1..].to_vec());
+        check_ops(pool.best_operations(3, 0), ops[1..].to_vec());
     }
 
     #[test]
@@ -462,7 +472,7 @@ mod tests {
             create_op(Address::random(), 0, 1),
         ];
         pool.add_operations(OperationOrigin::Local, ops.clone());
-        check_ops(pool.best_operations(3), ops.clone());
+        check_ops(pool.best_operations(3, 0), ops.clone());
 
         pool.on_chain_update(&ChainUpdate {
             latest_block_number: 1,
@@ -477,7 +487,7 @@ mod tests {
             }],
             unmined_ops: vec![],
         });
-        check_ops(pool.best_operations(3), ops.clone()[1..].to_vec());
+        check_ops(pool.best_operations(3, 0), ops.clone()[1..].to_vec());
 
         pool.on_chain_update(&ChainUpdate {
             latest_block_number: 1,
@@ -492,7 +502,7 @@ mod tests {
                 nonce: ops[0].uo.nonce,
             }],
         });
-        check_ops(pool.best_operations(3), ops);
+        check_ops(pool.best_operations(3, 0), ops);
     }
 
     #[test]
@@ -504,7 +514,7 @@ mod tests {
             create_op(Address::random(), 0, 1),
         ];
         pool.add_operations(OperationOrigin::Local, ops.clone());
-        check_ops(pool.best_operations(3), ops.clone());
+        check_ops(pool.best_operations(3, 0), ops.clone());
 
         pool.on_chain_update(&ChainUpdate {
             latest_block_number: 1,
@@ -520,7 +530,7 @@ mod tests {
             unmined_ops: vec![],
         });
 
-        check_ops(pool.best_operations(3), ops);
+        check_ops(pool.best_operations(3, 0), ops);
     }
 
     #[test]
@@ -534,7 +544,7 @@ mod tests {
         ];
         pool.add_operations(OperationOrigin::Local, ops.clone());
         // Only return 1 op per sender
-        check_ops(pool.best_operations(3), vec![ops[0].clone()]);
+        check_ops(pool.best_operations(3, 0), vec![ops[0].clone()]);
 
         let rep = pool.dump_reputation();
         assert_eq!(rep.len(), 1);
@@ -579,7 +589,7 @@ mod tests {
         // First op should be included
         pool.add_operation(OperationOrigin::Local, ops[0].clone())
             .unwrap();
-        check_ops(pool.best_operations(1), vec![ops[0].clone()]);
+        check_ops(pool.best_operations(1, 0), vec![ops[0].clone()]);
 
         // Second op should be thorottled
         let ret = pool.add_operation(OperationOrigin::Local, ops[1].clone());
@@ -610,7 +620,7 @@ mod tests {
         // Second op should be included
         pool.add_operation(OperationOrigin::Local, ops[1].clone())
             .unwrap();
-        check_ops(pool.best_operations(1), vec![ops[1].clone()]);
+        check_ops(pool.best_operations(1, 0), vec![ops[1].clone()]);
     }
 
     #[test]
@@ -650,6 +660,7 @@ mod tests {
             args,
             mock_reputation(THROTTLE_SLACK, BAN_SLACK),
             event_sender,
+            1,
         )
     }
 
diff --git a/src/op_pool/server.rs b/src/op_pool/server.rs
index f9ee47d93..cd38a7816 100644
--- a/src/op_pool/server.rs
+++ b/src/op_pool/server.rs
@@ -1,7 +1,7 @@
 use std::{collections::HashMap, sync::Arc};
 
 use ethers::{
-    types::{Address, H256, U256},
+    types::{Address, H256},
     utils::to_checksum,
 };
 use prost::Message;
@@ -23,19 +23,14 @@ use crate::common::protos::{
 pub struct OpPoolImpl<M: Mempool> {
     chain_id: u64,
     mempools: HashMap<Address, Arc<M>>,
-    num_builders: u64,
 }
 
 impl<M> OpPoolImpl<M>
 where
     M: Mempool,
 {
-    pub fn new(chain_id: u64, mempools: HashMap<Address, Arc<M>>, num_builders: u64) -> Self {
-        Self {
-            chain_id,
-            mempools,
-            num_builders,
-        }
+    pub fn new(chain_id: u64, mempools: HashMap<Address, Arc<M>>) -> Self {
+        Self { chain_id, mempools }
     }
 
     fn get_mempool_for_entry_point(&self, req_entry_point: &[u8]) -> Result<&Arc<M>> {
@@ -95,19 +90,13 @@ where
         let mempool = self.get_mempool_for_entry_point(&req.entry_point)?;
 
         let ops = mempool
-            .best_operations(req.max_ops as usize)
+            .best_operations(req.max_ops as usize, req.builder_id)
             .iter()
-            .filter(|op| {
-                (self.num_builders == 1)
-                    | (U256::from_little_endian(op.uo.sender.as_bytes())
-                        .div_mod(self.num_builders.into())
-                        .1
-                        == req.builder_id.into())
-            })
             .map(|op| MempoolOp::try_from(&(**op)))
             .collect::<Result<Vec<MempoolOp>, _>>()
             .map_err(|e| Status::internal(format!("Failed to convert to proto mempool op: {e}")))?;
 
+        tracing::info!("Returning {} ops to builder {}", ops.len(), req.builder_id);
         Ok(Response::new(GetOpsResponse { ops }))
     }
 
@@ -354,7 +343,6 @@ mod tests {
         OpPoolImpl::<MockMempool>::new(
             1,
             HashMap::from([(TEST_ADDRESS_ARR.into(), MockMempool::default().into())]),
-            1,
         )
     }
 
@@ -395,7 +383,7 @@ mod tests {
 
         fn remove_entity(&self, _entity: Entity) {}
 
-        fn best_operations(&self, _max: usize) -> Vec<Arc<PoolOperation>> {
+        fn best_operations(&self, _max: usize, _builder_id: u64) -> Vec<Arc<PoolOperation>> {
             vec![]
         }
 
diff --git a/src/op_pool/task.rs b/src/op_pool/task.rs
index 14e46287e..f1d78ebd5 100644
--- a/src/op_pool/task.rs
+++ b/src/op_pool/task.rs
@@ -71,14 +71,15 @@ impl Task for PoolTask {
         let mut mempools = Vec::new();
         let mut mempool_handles = Vec::new();
         for pool_config in &self.args.pool_configs {
-            let (pool, handle) = PoolTask::create_mempool(
-                pool_config,
-                update_sender.subscribe(),
-                self.event_sender.clone(),
-                shutdown_token.clone(),
-            )
-            .await
-            .context("should have created mempool")?;
+            let (pool, handle) = self
+                .create_mempool(
+                    pool_config,
+                    update_sender.subscribe(),
+                    self.event_sender.clone(),
+                    shutdown_token.clone(),
+                )
+                .await
+                .context("should have created mempool")?;
 
             mempools.push(pool);
             mempool_handles.push(handle);
@@ -99,11 +100,7 @@ impl Task for PoolTask {
         });
 
         // gRPC server
-        let op_pool_server = OpPoolServer::new(OpPoolImpl::new(
-            chain_id,
-            mempool_map,
-            self.args.num_builders,
-        ));
+        let op_pool_server = OpPoolServer::new(OpPoolImpl::new(chain_id, mempool_map));
         let reflection_service = tonic_reflection::server::Builder::configure()
             .register_encoded_file_descriptor_set(OP_POOL_FILE_DESCRIPTOR_SET)
             .build()?;
@@ -158,6 +155,7 @@ impl PoolTask {
     }
 
     async fn create_mempool(
+        &self,
         pool_config: &PoolConfig,
         update_rx: broadcast::Receiver<Arc<ChainUpdate>>,
         event_sender: broadcast::Sender<WithEntryPoint<OpPoolEvent>>,
@@ -178,6 +176,7 @@ impl PoolTask {
             pool_config.clone(),
             Arc::clone(&reputation),
             event_sender,
+            self.args.num_builders,
         ));
         let mp_runner = Arc::clone(&mp);
         let handle =