The guys at the paint shop said a little over a quart, so 2 quarts would do..
So how much do I put on? Just one light coat?

Then, how long do I wait to apply the build primer?

thanks.

one decent coat of self etching should be enough. you just need enough to bite into the metal so it will seal it better and not rust. i would let it cure for at least a day or two because that is nasty stuff and i wouldn't want any of those solvents to be trapped under a high build primer