About the only thing I use on frames is Zero Rust
. It stops rust dead, is a 1-part paint, available in gallons, quarts, and rattle can. The best part is that it is inexpensive (about $50/gallon). There is so many pluses that I don't even consider POR15 anymore.
It dries to a semi-gloss. For those areas where I want a gloss, I coat it with their Crystal Cote.