each finish you have used is a diff. animal in its own right's,the key to getting a great finish with any paint system is a test area, go to the wrecking yard and grab a car hood, leave it out side when not painting, but , bring it in and stand it up against the wall while finishing a project, you don't need to paint a very big area for your test, sand the hood and prime with an epoxy primer, that way all finishes will bond.