Best method of floor prep

[Gazoo]

I am looking at dynamatting or brown-breading my cab and after having lifted the old carpet and insulation, I have no major issues, but the expected minor surface rust. After some grinder-assisted wire brush action, and seam sealing the lower kick panels - what's everyone's experience as to the best prep material before installing the dynamat? Primer/Rust Paint? POR 15?

Thanks!