Ok this is the question. Lets say you have a stock Honda any will do. If you change the master cylinder size what will the effect be. Nothing else has changed its still all stock. Lets say both master cylinders have the same stroke.

Smaller diameter
My thinking is it will net you more gain. The smaller diameter master cylinder will build more psi in a shorter stroke. It will give you a better pedal feel by eliminating more free play.

Bigger diameter
This will move more volume of fluid but build less psi. Giving you a longer pedal stroke.

Your turn.