When you spray, you should do multiple coats at once. If the gel has set, you should likely sand lightly before going on. By the way... gelcoat needs to cure in a non-oxygen environment. The syran wrap will work, but it can wrinkle the surface. Find PVA ( sp? polyvinyl acetate ) This is a water based waxy coating sprayed on and then washed off later.
As I recall, spray coats with 20-30 second between. Spray thin coats rather than thick so they don't slump. Wait 5 minutes before the PVA.