Have you folks used this stuff? Can it be used directly over bare metal. Can it be top coated with Rustoleum???

I have a rearend that I wire wheeled and am getting ready to paint. I have Zero Rust paint as well as some etch primer. What would you use to cover the bare steel before I hit it with some rattle can Rustoleum black. This isn't a show car, just trying to make do with what I have.