Project Manager Fees

[K M]

Any advice on how to pay a project manager? I come from an engineering background and one method for bidding on projects is a 'cost plus' model. So cost of materials plus X%.

Would this model work with a project manager on a rehab project? Something like 20% over cost. So the investor would get multiple bids from each subcontractor, pick the best based on all factors (price, reliability, professionalism et al.) The PM would get paid based on when the draws are done for each of the subs.

This way the PM will not pad the cost of the subs so his % gives him a higher draw.

Does this make sense? Just looking at options for how to manage a pm.

Thanks!