Private lender loan structure

[Cale Snyder]

Hello all! I'm in the process of trying to buy my first flip property and have an interested private lender to help finance the project. However, it's also his first time lending on a flip (he focuses on rental loans), so I'm wondering if you have any insight on how we could structure our agreement so it's mutually beneficial for both of us. 

Right now we are talking about having him provide the funds to purchase the property, while I do all the rehab work and selling (just like a bank, I do the leg work, he provides the money to do the project in the first place). Would a basic percentage split of the profits between us be ok? Or is there a better system others have used? I intend on borrowing from him again should everything go well, if that changes the approach.

Thanks!