i ran these calipers on the back of my bug for a while - they were great
although i cant help with the answer regarding the fuchs - i ran them with 944T discs (24mm thick same as the 964 c2) and i also ran the 964 16" cup wheels.
one thing to note is if running with the 944 n/a backplate/handbrake bits i had to use a small spacers to centralise the caliper over the discs. 3mm iirc
hope this helps