He is willing to offer me a percentage of the deal/profits but we don't know how to structure it.My role will be finding the property and acquisitions (here ideally I will be compensated with a commission or finders fee if off market), and then manage the process until it is ready to be sold.I have read some posts about the project manager taking a % mark up on the cost of the rehab.

This will allow you to compensate for setbacks in the side gig.  

I would be thinking rents will be compensating 

Sorry to hear about your troubles.An thought, can you offer the tenant  a form of compensation, discount on rent for the inconvenience/utilities, tickets to a show.

By this time it had already cost us another $2550 in rent, plus we had to do (2) amendments with  the seller raising the price and reducing his seller paids as compensation for extending closing. 

What is my compensation for having my money tied up for 3-4 months longer than you promised? 

(3) All agents or brokers entitled to compensation from theproceeds of the property that is sold.

Is the tenant being compensated for his PM functions?

I do not have available funds right now but here is my spin, feel free to add/correct...Once you know how you are going to compensate your uncle it is pretty simple.

Read more here:   US Dept. of Justice on Realtor Rebateshttps://www.justice.gov/atr/rebates-make-buying-home-less-expensivehttps://www.justice.gov/atr/competition-and-real-estate-state-31FREC (Florida Real Estate Commission) Rule 61J2-10.028 paragraph (2)The sharing of brokerage compensation by a licensee with a party to the real estate transaction (i.e. the buyer or seller) with full disclosure to all interested parties is not considered a violationHope this helps.Good luck!