"The bigger the master cylinder is, the more fluid you get but you'll have less pressure at the caliper" (from Speedway Motors)
Different application but FWIW I ran in to this because I am putting 4 wheel discs on my truck and using a dual master cylinders. I called Wilwood and they recommended a 7/8" bore for the front and a 1" bore for the rear. More pressure in the front because that is where the braking is.
