I second Marq's comments about mmmmmmmmmm smooth surface prep. You can't spend too much time there.

Let me just add that paint "shrinks" in thickness as it hardens.

Soooo initially it can look like you "covered up" those scratches. Once cured, however, the scratches can magically re-appear as the paint dries down in those valleys Marq was talking about.

That is why you always sell an Maaco car right after it is painted. There is no telling what surprises await you when it cures...