I think this is as hard as you make it. Only key for me when I start a venture with multiple people is how trustable and logical the partners are. That way you

I think this is as hard as you make it. Only key for me when I start a venture with multiple people is how trustable and logical the partners are. That way you know if you ever have to re-do the ownership at any point, you might not get exactly what you want but you will still get something very close to fair.