2k urethane or epoxy primer?

I have been painting cars for 20 years now and have used this combination on most of my restoration jobs. From start to finish: bare metal car. First either epoxy or etching primer, then polyester primer (blocked) then, 2K urethane primer (blocked) then, 1K sealer or a base coat for coverage (mainly white, grey, red, black, etc depending on the color you are shooting. Example, if painting sassy grass start out by basing the car in white) then, the base color then, clearcoat (block), then clearcoat again (block). if painting a single stage, insert that where it says base color.
I know it's alot but hope this helps.