I am installing AC in my 914 and have all new parts, hoses and condenser. The evaporator has been cleaned out. I cannot find any data on total system refrigerant oil capacity. Since all the hoses and components are new, i figure 6 ounces (??) is a good place to start. The compressor is new (Sanden) and I will drain and refill it to determine how much oil is inside it. Just to be clear, the amount of oil inside the compressor is part of the total oil system capacity, yes?
Any advice will be greatly appreciated.

Are you doing R12 or R134?

Total capacity includes compressor. Rule of thumb if no specs are available... 4oz in compressor, 1.5 in condenser, evaporator 1.0 small amount in lines and 1oz in receiver /dryer.

I've never seen one of these systems. What type of expansion device is used? TXV or orfice tube? R12 or R134a? Also, what refrigerant is the system originally for? If R12, then about 80% capacity for R134a. Again if there is no spec, you can fill as needed after evacuation.

According to their installation manuals: VPC system required 28 oz R12, DPD requires "2-1/2 pounds R12, 3 cans is too much."

It's an R12 system that the previous owner had removed. The only original piece being reused is the under dash evaporator. It now has a 63 Buick Aluminum V8. The compressor is mounted and the new condenser is in front of the radiator.