Paul, seeing as how he will be the last person to have anything to do with making it, he will probably be the one to keep it. Plus, since it was his idea originally, don't you think it should be his? If you were to get anything out of the deal, I would expect it to be praise and possibly a few dollars for your work. What do you think, would you be alright with that? Up front is the time to figure out who is going to get what out of the partnership, doing so makes for a better ending to the partnership. Of course, you guys could always make two of whatever you decide to make, then both would end up pleased.
Len