On Sunday, April 9, 2017 at 9:35:00 AM UTC-4, wrote:
I have done it both ways, but prefer polyprimer because it is white!
Another tid-bit I have tried is to wet sand with 800 grit after 12 to 24 hours cure, then buff out right away. Shines like no tomorrow, believe the paint is moving under buffer, just enough to eliminate the 800 sand marks.
JJ

The extra step I now do with white epoxy primer makes me more comfortable that I have a really good surface before I spray finish. I put disclosure coat on and wet sand with 400. I find that, for me, it avoids unhappy surprises. It does add more time for sure.
I sand the paint out with 1500, then 3000, then buff. I sand on the 3rd day, or later. JJ's methods are quite a bit faster.
Not sure what Andy and Heinz are doing.
FWIW
UH