. Build a frame from 1x2s, a couple packs of hinges mounted on the frame edges let you fold it flat for storage or open quickly, get a plastic sheet painting drop cloth to staple to it. While it's popular to hang a guitar body vertically from a stick of wood screwed to the neck pocket, it's better to build a fixture so you can stick the wood stick into a pvc pipe so the body is horizontal and then rotate the stick+body. That way when you spray the front or back of the guitar the paint can lay on the face rather than shed itself like rain water. This horizontal mounting method will cause you to build a bigger booth but the finish quality will be better. .