Owner Finance or Master Lease or ???

[Tom NA]

I'm looking for advice on a property that I own free and clear where I have a potential buyer that I'm negotiating with. We're trying to find terms that work for both of us and I think we're close. Let me give as many details as possible:

Property: Duplex
Unit 1: 2 bed/1.5 bath - rented at $450/month
Unit 2: 1 bed/1 bath - vacant with market rent of $375/month

My needs:
None in particular - no need for the cash so I'm happy to finance, even for an extended period of time. The most important thing to me is to structure so that if I have to take the property back that it isn't too painful and doesn't cost me too much. The only reason that I'm considering selling vs. continuing to hold and rent out myself is just the ongoing hassles of dealing with property managers from afar and the difficulty keeping both units occupied. I have no problem continuing to hold the property and will do so if I don't get a deal that I'm comfortable with. Additionally, this is the one property that I own free and clear which makes it an obvious candidate to sell at a premium because of the financing that I can offer a buyer.

Buyer's needs:
Minimal or no down payment. Long period until balloon payment due. More concerned about limiting initial outlay than with final purchase price or interest rate.

What we had agreed upon several months ago before he got caught up in some other deals:
Purchase price: $52,500
Down payment: $2,500
Owner Finance balance at 8.5% - payment $384.46
Balloon due in 10 years, can prepay at any time

Now that we have re-engaged, he has asked for 100% financing or perhaps a phased down payment over the first year. My concern is that this leaves him with no real skin in the game which increases my odds of needing to foreclose. An alternative that we have talked about is a Master Option agreement, which I'm not very familiar with. It appears that agreement would keep me as the owner but he would have full legal authority to improve the property, perform maintenance, and rent it out as he sees fit. Basically, it's my property but he controls it as I understand it. I still have title, pay property taxes, insurance, and perhaps even utilities on the property. The nice part of this option is that I don't need to foreclose if he violates the agreement. I just take back control of the property and he's out of the picture without any expensive legal process required.

So he's open to different possibilities and I'm looking for advice. He's suggested we could raise the interest rate and/or purchase price if we pursued the Owner Finance option. My concern is that wouldn't really address my concern about needing to foreclose. That leaves me wondering if the Master Lease might be a good choice. I could charge him something on the order of $550-$600/month which would leave me with about $400/month cash flow and that leaves him with ~$250 that would need to cover all of his expenses. Obviously, I'm not worried about 50% rules here, which may suck up all of his potential profit. I'm worried primarily about my outcome.

Thoughts appreciated!