I don't think the size of the cylinder bore has much to do with pedal pressure. The length of the pedal (pedal ratio) has more to do with the amount of foot pressure needed to apply the brakes. The master cylinder bore size has to be matched to the size caliper pistons. Disc take more fluid than drums. The pedal should not over travel the mc piston, bottoming out. This will damage the master cylinder. So pedal travel = mc piston travel = correct amount of fluid to the wheel calipers so they travel the full range to close the pads. or something like that.
There is a lot to a well engineered brake / clutch system.
There are a few guys on this site that know a lot about brake systems. Let hope they post so we can all learn.
Dwight