I've been going with a nominal 10% based on the performance from some of my other properties, which admittedly could have been pure luck.  

The A/C guy just put more freon in it, he basically patched it up for another year.....Also with a heat pump the techs DO NOT put extra freon in your unit when they installed it to compensate for the 50-100 foot lineset/pipes that run up the wall, so you are already short on freon the day they install the unit, you just dont know about it....If you went with a package unit (the square rectangle kind that is all outside) you shouldnt have to worry about being short freon because  its precharged from the manufactor (I trust them more than a green helper that just started in the A/C business), and you shouldnt have to worry about carpenters, or sheet rock guys punching a nail threw the pipes that run up the side of the wall because its all self contained in that outdoor unit...Thus they call it a "Package Unit."

The bank would rather see those notes turned back into performing assets than to foreclose on the property, even if you increase the value of the property. 

He is paid a salary, two raises since he started, exceptionial performer, without being tied to specific preformance criteria, mostly because I couldnt figure out the criteria.

I don't care about a "Comp" I want to evaluate the performance of the property.

The taxes and insurance (homeowner's policy) are in the buyer's name, paid for by me (additionally insured) as part of their monthly payments.If the property needs work, or upcoming repairs (new roof, windows, etc) I include these improvements within the contract with a penalty cost if not performed by agreed date.

Although, ironically, our 'bad neighborhood' purchase has performed well.

Depending on where exactly the property is will determine what type of tenant you will have which will dictate how it performs in the long run.  

So you can assign or resell (sublet with the lease and re-option with the option) either of them.Therefore, you have multiple ways to structure this depending on how long you want to be involved and how much associated risk you are willing to take.With the lease, you can assign it for a fee and be done or you can sublet it where you are still on the hook for the terms of the lease, but can receive the difference in rents for the entire term.With the option, you can sell (assign) the option and be done or you can option your option understanding that performance will require a double close.  

And finding a broker to sponsor, some have performance quotas and can release u if you dont produce.