--- a/firmware/platformio.ini
+++ b/firmware/platformio.ini
@@ -13,8 +13,8 @@
     fastled/FastLED @ ^3.6.0
     cameronbrooks11/CRUMBS @ ^0.16.0
     cameronbrooks11/bread-crumbs-contracts @ ^0.9.0
-    cameronbrooks11/LMD18200 @ ^0.1.4
-    cameronbrooks11/DCMotorServo @ ^1.0.1
+    https://github.com/CameronBrooks11/lmd18200.git#b11192a20a25cb2521fbc652f51a2ffc4b977d9c
+    https://github.com/CameronBrooks11/DCMotorServo.git#cc8bad6c9c605249a916d74a17a1adffacab0143
     paulstoffregen/Encoder @ ^1.4.4
 build_flags =
     -DCRUMBS_MAX_HANDLERS=12
@@ -59,3 +59,19 @@
 build_flags =
     ${env.build_flags}
     -DDCMT_HW_GEN=2
+
+; ----- Bench image B: unreleased library main branches, bench-only flags -----
+[env:bench_b]
+extends = env:gen2_nanoevery
+
+[env:bench_b_lead300]
+extends = env:gen2_nanoevery
+build_flags = ${env:gen2_nanoevery.build_flags} -DBENCH_MAX_LEAD=300
+
+[env:bench_b_lead900]
+extends = env:gen2_nanoevery
+build_flags = ${env:gen2_nanoevery.build_flags} -DBENCH_MAX_LEAD=900
+
+[env:bench_b_acc300]
+extends = env:gen2_nanoevery
+build_flags = ${env:gen2_nanoevery.build_flags} -DBENCH_ACCURACY=300
--- a/firmware/include/config_hardware.h
+++ b/firmware/include/config_hardware.h
@@ -48,7 +48,11 @@
 
 #define DCMT_SERVO_PWM_SKIP 15
 #define DCMT_SERVO_MAX_PWM 150
+#ifdef BENCH_ACCURACY
+#define DCMT_SERVO_ACCURACY BENCH_ACCURACY
+#else
 #define DCMT_SERVO_ACCURACY 10
+#endif
 
 // Speed-loop update interval in milliseconds.
 #define DCMT_TACHO_INTERVAL_MS 5
--- a/firmware/src/main.cpp
+++ b/firmware/src/main.cpp
@@ -439,6 +439,10 @@
     apply_speed_pid_if_needed(slice);
     tacho1.setSpeedRPM(0);
     tacho2.setSpeedRPM(0);
+#ifdef BENCH_MAX_LEAD
+    tacho1.setMaxLead(BENCH_MAX_LEAD);
+    tacho2.setMaxLead(BENCH_MAX_LEAD);
+#endif
 #endif
 
     slice.motor1Position = clamp_i16(servo1.getActualPosition());