Are you going for a bias pedal box? Normally the likes of comp brake sell you the spec of master to match the car. I have a comp brake kit here that I was running on my 4x4 and it worked well, it would probably fit your car as it just bolts on to where the servo would bolt to your pedal box. The problem with bias boxes is you have to push hard, this is fine but as I have 5 cars I was getting in the modern stuff and nearly flying through the windscreen as my leg had got used to the shove needed on the non servo setup.

I can look on mine to see the sizes, I used ap cylinders and the rear is different to the front.