I feel that the coinvest should be meaningful enough to cause real pain for the GP in the event of a bad outcome, but not so much pain that a bad outcome or 100% loss ruins them or threatens to disrupt their lifestyle either. 

Ask them what their biggest pain points are, then figure out how to solve their problem.

With $15k toward closing costs, a buyer should be able to get a significant rate buy down and rate is a major pain point right now.

Or you can try to figure it out on your own but it will be painful process but at least you will have some battle wounds.

While it may be difficult to pay a defaulting tenant and waive the delinquent rent in order to motivate the tenant to vacate immediately, it is far less painful than having to wait until the moratorium expires and then pursue an eviction.

The closest place to me that sends overnight closes at 5:00 and the next closest is 30 minutes away (Still closes by 7:00) and of course buyers not getting home till 6:00 makes for a 48 hour turn around a bit of a pain.

These rules can be a pain but they are fund EVERYTHING so you know. 

I feel your pain, very much so!

You're not going to walk away exclusively with feelings of pain or pleasure as-in feeling like you "paid for nothing" or "overpaid" if no defects in the sewer line are found OR feelings of "it was worth every penny" or "thank god I had it done" if defects were found. 

I have a rental portfolio of 15 properties and a primary residence on a mortgage. 4 of which are in Indiana and plan on selling those this year. 6 single family homes in Pa in the same area and 2 duplexes (2 units each) .