Ron, I can make a suggestion that is a combination of what you want to do and what everyone is reccomending. On a total repaint I did I used laquer primer as a block sanding guidecoat. Now you could use it for your first primer solely to keep the metal from rusting. When I was done blocksanding there was very little primer left on the car and I recoated over that with a primer sealer that was catalyzed. You could do the same. When you're done with bodywork and such, block the body down to remove most of the laquer primer and reshoot the whole vehicle in sealer. You will now have a very tough primer that will seal the primer from the top coat and an added benefit is that modern sealers are so good they don't allow the metal to rust like old primers that were porous. Of course if you're willing to change your habits then ditch the old primer except as a quickie guide coat for block sanding.
Joe
