On the Schwatrz chassis I'm getting it will have manual brakes with 13" wilwood brakes 6 piston front 4 piston rear. Jeff told me to he uses a master cylinder for a 70 corvette for this application. Cheap and works great. My be your answer.
13" wilwood brakes with 6 piston fixed front calipers and 4 piston fixed rear calipers is a lot larger caliper piston area than a big bore 2.75" metric caliper front and 7/8" wheel cylinders in the rear. Schwartz says to use a 1970 Corvette manual master cylinder with a 1” bore. That bore size is comparatively small compared to the brakes it supports. I am not saying their wrong. It just proves a point that you do not need a big master cylinder to have good manual brakes. Your master cylinder needs to be sized proportionately to the brakes you are using.