I think you're overthinking this. I have used Polly Scale Red Oxide primer for 6+ years on 20+ tanks with no problem. IMO Polly Scale is better then Tamiya, almost no smell and thins with water. Their Red Oxide comes in both 1/2 and 1 ounce bottles in acrylic and enamel. There will be no problems laying Tamiya paints on top of it either.