I'm replacing most of the components of my AC system in a 1970 280SEL -new compressor, receiver-dryer, hoses, and expansion valve. Only the condensor and evaporator will be re-used. The system had not run in years and was leaking, had sludged up oil, and did not hold a charge. My question is 'how much refrigerant OIL goes into the entire system before putting the refrigerant in? And I'm sticking with R-12 if that makes a difference. The instructions on the new compressor say to 'not exceed the maximum amount of oil listed in the vehicle service manual.' Does anyone have that number?
What I've heard from a number of sources is that the typical amount of refrigerant oil in an AC system is 4 oz., but when we drained the new compressor before installing it, there was probably 3 times that amount in it. It has me scratching my head and wondering.

Thanks!
John