Sorry I'm late to the party!

Use rust converter on the metal or any little bits will keep growing. Primer is thick and easy to sand and helps the top coat stick but is porous and holds water so primer over bare metal is like a damp rag on it the whole time.

1) Rub with a steelo then brush on Rust converter.

2) Primer, Sand, Primer, Sand.

3) Top coat, Wet sand (fine), Top coat, Clear.

Looks like you had fun and it didn't take too much time or money so good on ya!