How should the proceeds be split between the artist and the writer?
That’s a question of negotiation. You each have to decide what you want, and compromise. — Donna Barr It’s for you to decide. Whatever you do decide to do, you should spell it out in writing. You needn’t go overboard with a fancy contract, just document the whats, whens, and how much. Just the act of writing it down will help prevent misunderstanding later on, and the agreement will be legally enforceable as a bonus.