Kind of a open question. What type of bc/cc system are you using? Depending on that will make a difference. A good quality base I would figure at least 1gal and 1qt. . You will use up a 1qt. and then some to jamb car. I always like to have a little extra if possible for future work or in case of a accident. Don't let someone talk you into one of the many low end systems out there. It seems nowdays everyone trying to do things cheaper when it comes to paintwork. Be up front and ask what is getting used and do some research on your end too.any other questions feel free to ask.
Joe