What are you using for Rust Converter? I usually get Rustoleum, but last night picked up Loctite's version as it said it's supposed to be a little glossy.
I use different stuff in different places.
Evaporust works great if you can soak stuff for days (or weeks.) I've put rusty nuts, bolts, screws, tools, etc. in a bucket of the stuff, let it sit for a long time, agitate a-periodically, and the results have been impressive. I should note that stuff I've treated with Evaporust does rust again, so it doesn't create a shell like some other products.
Krud Kutter (gel right now) works amazing on surfaces you need converter to stick to. Was using it under the jeep. Cleans up with denatured alcohol for priming and painting. They claim up to a year of protection after treatment, if you don't top coat the surface. I'd try their liquid stuff if I wanted something faster or more aggressive than Evaporust.
Finally, POR-15 appears to be doing great under the jeep as well for large coverage areas. I'm happy with the initial results.
Obviously, YMMV.