Also, I firmly believe there could be SUBSTANTIAL differences in the chemistry that affect the performance of the Tremclad vs. Rustoleum.

I have been on the receiving end of different formulations of paints, resins, gel-coats, etc., that were mandatory at our shop in So. Cal., and not at our shop I had in No. Cal. Same can, same colors, same except the difference in formula for emission control compliance, and a WORLD of difference in performance.