Constructing this contract - wholesaling an O.F. deal

[Dave Rav]

Hello group. So, I am attempting to write up a contract on a wholesale deal. Caveat is, this deal is super lucrative as it offers Owner Financing! My big question is: How do I factor in my fee? Initially, I am thinking just increase the amount the end-buyer brings to the table (their down payment, essentially) 

I am thinking of tacking on a few thousand to end-buyer's down pay. Thoughts?

*disclaimer: Seller is aware I am wholesaling this deal. Gave them full disclosure, so they understand what is happening. Seller is an investor known to me, and agrees with this method of sale.  

Thanks, all!