Used to have a 61 Westy w/Fuchs alloys. Had a 71 balljoint/disk brake
frontend (same bolt pattern as Vanagon) and a Bus Boys IRS rear with Type 3
4-bolt drums. Had FAT Performance drill and install Porsche pattern  on the
rear but there wasn't enough meat on the front so had to go with adapters
from FAT. Later I ran into a guy who added the necessary "meat" to the front
rotors by welding about 1/2" plate to them so he could add the Porsche
pattern studs and avoid the adapters. The 61 was a lightweight compared to my
Vanagon Westy. Don't know if I'd be so confident using adapters now except
maybe a non Westy.

Ken Hunter
82 Westy 1.9D
84 Jetta 1.6D
89 Mitsubishi van