Partnering with a GC - what % would be good?

[Elizabeth Cook]

We're considering partnering with a GC who is a good friend of ours. We will be purchasing a SFH and paying for all of the rehab, so we'll have all of the risk. The GC has all the rehab experience and contacts. If he gets a percentage of the net profit, then he's incentivized to keep costs low. How much markup does a GC generally charge investors? Or better yet, what percentage of the net profit would you offer? Would you suggest some reduction of percentage points for going over estimated time? Any other conditions that I'm too new to know about? Thanks so much!