[Jeza]

I'm also in a similar boat.

944 single piston calipers all around and a stock bug 19.06mm master cylinder.

I also have a fair amount of pedal travel and quite a bit of squish. It does get firmer with some pumping but I'm pretty sure I've got the air out of there. I'm not getting any air when the calipers are bled, unless it's hiding elsewhere.

I've been suggested to check out shimming down the front pistons instead of using the 944 mc. The reason behind this is that the 944 is a front engined car and the brake balance will be set up as such.

I reckon if the front calipers are approx 44mm diameter the front to rear ratio will be about right, and similar to the CB kits, just bigger and vented.

Do the 4 pot calipers have less volume / fluid area? The 4 pistons make them more efficient. This may effect the pedal feel.

Hopefully this sparks some thoughts

Cheers
Jeremy