diff --git a/ext-configs/settings.yaml b/ext-configs/settings.yaml
index 8c66b35..a71c984 100644
--- a/ext-configs/settings.yaml
+++ b/ext-configs/settings.yaml
@@ -149,7 +149,7 @@ chunk_method: hybrid_uss
 # production
 # disabled
 # assume enough RAM to not chunk
-chunk_training_mode: disabled
+chunk_training_mode: explicit
 
 # whether to preserve or delete subprocess chunk and mem logs when they are consolidated at end of multiprocess run
 keep_chunk_logs: True
diff --git a/ext-configs/vehicle_type_choice.yaml b/ext-configs/vehicle_type_choice.yaml
index d0b9a91..fdf81ee 100644
--- a/ext-configs/vehicle_type_choice.yaml
+++ b/ext-configs/vehicle_type_choice.yaml
@@ -4,6 +4,8 @@ SPEC: vehicle_type_choice_op4.csv
 COEFFICIENTS: vehicle_type_choice_op4_coefficients.csv
 ALTS: vehicle_type_choice_op4_alternatives.csv
 
+explicit_chunk: 25000
+
 # SPEC: vehicle_type_choice_op2.csv
 # COEFFICIENTS: vehicle_type_choice_op2_coefficients.csv
 # ALTS: vehicle_type_choice_op2_alternatives.csv
diff --git a/performance-benchmarking.yaml b/performance-benchmarking.yaml
index d4731e7..fe65149 100644
--- a/performance-benchmarking.yaml
+++ b/performance-benchmarking.yaml
@@ -37,7 +37,7 @@ steps:
       trace_hh_id:
       trace_od:
       chunk_method: hybrid_uss
-      chunk_training_mode: disabled
+      chunk_training_mode: explicit
 
 - name: activitysim.workflows.steps.pype
   in: