Gillespie paint+primer moisture resistance

[red devils dude]

here's a quote from a guy who is restoring a GPW

I use "Dupli-Color" or "Plasti-Cote" brand red-oxide colored primer sold in spraycans at the local autoparts stores. This stuff seals the surface better than the Gillespie primer which is porous and allows moisture through to the metal and rust to set in, even through the OD paint!

he seem's to know what he's talking about so I thought I'd ask for
our member's opinion.