You might want to go with automotive grade 2k clearcoat instead. The coating is a lot harder and more durable than regular stuff. However, PLEASE use a respirator with a proper filter (P95?) and use in a well ventilated area because the spray is hazardous to your lungs.
You can find 2K clearcoat at Lordco. I tried using it to clearcoat my wing and honesty, it's real close to what you get from an average body shop given the proper preparation.
Spray Max 2k High Gloss Clearcoat aerosol