Glad to hear that you are bringing to life another Borgward Coupé.
When you install the Clutch Slave kit and Clutch Master Cylinder kit be sure to replace the hose connecting them. A brake service place or even NAPA could make up one from looking at the original.
Wheel cylinders are available, but if you can "re-sleeve" the old ones (a brake service place) that will do just as well and is probably less expensive.
1. Brake Master Cylinder Kit: Wagner - WAF F31066; NAPA 234
2. Clutch Master Cylinder Kit: Wagner – F93000; NAPA 225
3. Clutch Slave Kit: NAPA 328
Also: Raybesto - CSK255
Dyck Livant also has parts and info on the BOC club and dues. Where are you located?
in Minnetrista, Minnesota