MY only thought is that it takes a bigger compressor, or a large storage tank, to use an HVLP gun. It means high velocity low pressure, and needs a large volumn of air. You won't know until you try it, whether you will run out of air pressure too soon.
The paint I mentioned, I bought at the local Ace. I don't know if it needs primer, but with a name like Rust Stop, I doubt it.