If you are using a two component paint, reduse the hardener to 60%-70%, and allow the paint to harden 24 hours moore before touching it.
Remember to keep the temp up.
Your hingeline will be invisible, and it works fine. I assume you mean a all - over sheet hinge..?

If you are afraid about the reduced amount of hardener, have no worry, the trick is twenty years old.
This method is widely used in car painting, when it comes to soft spoilers and so on.
I surely would go for this one...

Gudmund