Building a flip partnership with a GC

[Anthony Caiafa]

I have seen a few threads on this but haven't really seen much concrete information. I have a GC that has built multiple houses for me personally to live in. He is a solid person and we are going to start working some deals together. He has his hands in a lot of different things and made all of his initial money off his contracting business. His staff is great and everyone is real tight. 

I am trying to figure out howto chop this up. I myself will be finding / mortgaging the homes. I will pay the monthly on the note and the taxes. I will be doing the designing of the interior of the house after all the initial work is done. I will be onsite on every house working with the GC figuring out what we want it to look like as an end result. He will be doing the work. I will be selling the house after that. I am 100% going to do a 50/50 split with him. My only thing i am curious about is how people formed the partnership agreement. Besides sweat equity i feel like he has to put money up also. All renovations and budget we would agree on and either split it or he takes on the entire cost and takes it out at the end. 

Thoughts? Ideas? comments?