I have a set of almost new Brembo GT1/F50 calipers with 40/44mm piston sizes left over from when I sold my other car.

I was thinking of installing them using custom hats and 993tt rotor rings. I already have a set of MBT engineering 'blank' brackets that would have to be machined for this application.

My mechanic thought that these may be too big for the master cylinder to handle (too much pedal travel or hard/soft pedal).

I know that 993tt calipers have 36/44mm pistons. Any thoughts?

(60mm/2)^2 is > (36mm/2)^2 + (44mm/2)^2, so the big reds have less piston area.

That doesn't correlate with what my foot is telling me, either. I think there is more pedal travel too. What am I missing?