I suggest making at least three new linkage set ups , before kicking the shit out of an inanimate object when it's worse......
I'd measure degree of both original set ups , compare first, check Weber hasn't any progressive linkages etc on the carb itself.
Depending on what set up you're currently using, have you got the same amount of travel after it's turned 90 degrees?
Measure travel on the cable to WOT , that'll dictate where the cable needs to be attached on the first lever, as above, and that is then sufficiently opening the throttle, wrong ratio and you'll be going through a wall with an inch press on the loud pedal, wish I'd paid more attention on physics/maths instead of dreaming of Linda Lusardi.....good luck!
Thinking about 5 pedal, cable is quite a long way from pivot, R8 ( imagining it's similar to Daup/4cv ) it's fairly close to pivot, as it sits below ??? As in cable is under slung on 8 ,going to the back of the car, over slung on 5 going through bulkhead.....I might be talking bollocks, but that's what's in my head