I don't think putting clear coat over rustoleum would be a good idea. It probably would not be compatible. It was as shiny as real single stage any place that wasn't scabbed.
I have seen people make comments about this type of paint job saying that real single stage doesn't cost much more. Good luck shooting single stage in your back yard with minimal prep. Real paint requires real prep, and in my opinion can be a real waste of time and money if you don't do it 100% right.