Hello Marco!
Well, original 17mm bug M/C is not the ideal choice!
Your options are a lot including : 911,944 Kerscher and even from a Bay window non-servo assisted M/C 23 (!) mm is very good choice
Good luck with your car!
P.S. I would love to see some photos from your engine ;
my address :
vw_wasserboxer@yahoo.gr