Either decide how you want to do it and find an artist that will do it that way, or find an artist you want and do it the way he wants. Or maybe you'll get lucky and find an artist that you want that wants to work they way you are dictating.
My artist likes to outline first. He outlined my whole back in one marathon session. Just my opinion, but I only want my artist thinking about making great art. I don't want him thinking about limitations I'm putting on him.