I need to put the right amount of peg oil into my new compressor and condenser. the system no longer has vacuum because of an accident, so I don't think I'll be able figure out the required volume by draining what is already there, which is the method that the manual provides. is there truly no other way to know the right volume? I've been looking online and it feels as though the right amount of peg oil is a protected secret or something. I just need a number of milliliters. any suggestions would be appreciated. thank you!