[bry593]

Just wanted to provide an update on this thread.

I did end up adding a brake valve and reduced the rear caliper piston size from 2.00" to 1.75". This allowed me to tune the discs so that the rear brakes do not lockup in a panic stop. This resulted in excellent braking.

I used a BAER valve and mounted it in series with the existing GM combination valve. This compounded the effect and provided full control of the brake tune. It also allows me to dial in a few turns when hauling a load or pulling a trailer.

If you are interested, I made a video showing some of the details:
https://www.youtube.com/watch?v=_WWka224rgs