figuring out master cylinder size for caliper question.

[bryant]

so ive been searching all over the net for a clear formula or calculator for figuring out master cylinder size and cant find anything definitive.
i find plenty of stuff about pedal ratio and bore size pressure equations but none factor in what the caliper piston sizes are.
what i have right now are these specs
a pedal ratio of 6 to 1
a master cylinder of 15/16"
wilwood 4 piston calipers on all 4 corners
wilwood lists the front calipers as having a piston area of 4.8"
and the rear calipers having an area of 3.0"



so what ive figured is that i have 960 psi with 150 foot pressure force according to these calculators http://www.wallaceracing.com/brake-master-cyl-calc1.php

im experiencing a lot of pedal travel with a squishy feel that seems like air is in the system but i have bleed it thoroughly and am confident i dont have air. every thing indicates that i have to small of master cylinder. the brakes stop fine and i can even lock them up if i push the pedal practically to the floor and when i get caliper kick back during the autocross, the brake pedal needs lots of travel before its effective.

i cant find any into that tells me with my caliper piston size what size master cylinder i need to go to.

i know right now from the way the brakes feel and perform i need a bigger master cylinder. ive seen lots of references to using a 1" master cylinder on mavericks with brake setups really close to mine. its just such a small step op from my current 15/16"s mc that going to a 1 1/8" seems like it should get me closer to what im expecting for pedal feel and performance.

so the question is what size master cylinder should use?