how to structure this deal?

[Robert Fornwalt]

how should I structure this deal?

a fellow Reia fix and flipper has almost completed a rehab.  but ran out of cash to finish. the project needs a new roof and some windows need to be replaced. all in all about $8000 to $10000 should cover it. he is looking for a short term loan maybe 2 to 4 months.

so how should I structure this?

-do I charge interest? and how much? it could take more than 4 months to sell. but it looks like it will go quick. not overpriced. 

-do I just charge a flat fee? 

- just take a percentage like I'm a partner in the deal?

if I did it like a short term loan say 10k @ 12% and it only goes 2 months not sure it would be worth it?

any help would be appreciated