Doing research for my build, and I came across this study comparing the rust conversion properties of different brands.
It compared; Rust Reformer, Ospho, Corroseal, RC x 427, CCI Recipe, and untreated.
TL;DR... Rust-Oleum Rust Reformer performed the best.
https://www.ncptt.nps.gov/wp-content...l-paper-88.pdf