How much Primer?

2 qts of each will be enough. You will have 6qts sprayable with the hardeners and more if you add the 1/2-1 part reducer. 2 coats is more than enough especially if you don't reduce it. It does layout nicer with some reduction. The DP isn't made to be used as a build primer but if it sets long enough(months) it does sand okay.

Bob
PPG paint store asst manager