Regarding an alternate MC, I did a bunch of searching for stepped bore designs, being familiar with MICO products, and ended up with this. It works great. I also have 10psi check valves in both the front and rear brake lines.
https://www.fordbarn.com/forum/showp...98&postcount=5
The whole thread is here,
https://www.fordbarn.com/forum/showt...nder&showall=1
Glenn