DPLF is the new lead free version of DP. It was never the same once they took the lead out. It can’t be sanded and the price is outrageous for what it is.
Epoxy can be used with any solvent or waterborne paint.
For sealer I use reduced SPI epoxy. There is a lot of information in the tech sheet on their website.
So my usual build is bare metal, SPI epoxy, filler and/or polyester primer in the epoxy recoat window, epoxy, urethane primer in the epoxy recoat window, and reduced epoxy sealer just before base coat.
Sort of hijacking this thread.
You can PM me if you have more questions.
Don