sealer

Hey guys Awhile ago I sprayed 3 coats of SPI epoxy primer on the underside, inside and trunk of my 67 chevelle. I need to seam seal everything still and have a few questions. - Does the seam sealer need to be top coated with paint after? I wasnt going to topcoat the epoxy since it isn't needed...

If I sprayed a few coats of epoxy on a bumper cover and let it sit in the sun for the majority of a 65+ degree day, how does this effect the recoat window? I'm assuming it's much shorter, but if so..how do you determine when that window is still open?