Well, this I'm not sure... If it’s very old it will remove some of the paint. The effect wont be good, we tested on acrylic paint and it didn’t effect so well. Remember this is not to replace clear coat!! Clear coat has 20~30 microns minimum.
6.-Consider a car with older single stage paint that is badly oxidized and faded and then polished to perfection and brought back to glossy condition. Will Cquartz lock in the gloss or have any effect stopping the paint from regressing to its faded condition?
I’m not sure about that and can’t give you an exact answer. We usually use it on normal car painted in Europe.
7.-Should you expect any color transfer from single stage paint onto your applicator if you later apply a second coat?
I think yes, but you need to try yourself.