FWIW, changing the bore size of the MC increases/decreases the leg effort for a given amount of stopping force, it doesn't change the overall stopping ability of the brakes.
As always you give something to get something. If you decrease the bore size of the MC you will increase the pressure in the system for a given amount of force applied by the leg at the expense of having to move the pedal further to have the shoes contact the drums. Conversely if you increase the bore size the pedal travel is reduced but it takes more leg power to get a give amount of pressure in the system.
