Epoxy or Urethane High Build... what's next for me?

I agree with all the above and yes I use epoxy reduced as a sealer before topcoat, maybe overkill but works for me. I like SPI epoxy, and good tech guy..
My routine is metal work, clean it, epoxy primer, filler, epoxy primer, high fill primer, epoxy primer sealer, topcoat. But I admit I no pro!! Just a hobbiest for 35 years, or is it 45???? I forget.