I’m doing a frame off resto of a 64 GTO. I stripped the underbody mostly to metal, treated rust mechanically, then sprayed the 2 part rust convertor. Today, I top coated that with rust encapsulator. If I intend to use Extreme Chassis black on the underbody, do I need to add another coat of the Chassis black primer? Thanks, and so far, the products have worked extremely well!