Am reworking a 1979 320, has very little rust (so I thought). Typical places, rear shock towers, trunk, etc. Now the question - how do you deal with fixing the rust?? Has anyone ever used the "metal treatment" which turns the rust to a black primer then epoxed primed, fiberglassed & painted? Plan on driving the car and want to fix it to last, I just don't want to start cutting & having to weld in metal.