How to convince seller to owner finance duplex?

[John Marlin]

Hey BP peers! I'm an experienced investor in single-family houses, looking to get into multi-family next. I recently met an investor who informed me he'll be looking to sell a couple duplexes and a triplex in the next couple of years as he's getting older. How best should I go about presenting him a potential owner finance deal at a fair market value on one of these properties that would be ideal for both of us? Here's a few main points. 

1. He's specifically waiting to sell only one property each year, to not get kicked up into a higher tax bracket and pay more capital gains than he has to. How might owner financing potentially reduce his tax liability?

2. He wants a fair market value, and duplexes here are harder to come by, so I'd be happy to pay accordingly, but want to make sure I'm cash-flowing, but likely might not have 20% down to pay unless I sell or refinance another property. Any creative approaches to financing here that would be enticing to a seller? 

All in all, I don't have much experience with owner-financing, but being a 1099 self employed person, owner financing will likely be my best option. Again, the owner is older, and owns these properties outright, so I believe keeping the consistent income might be enticing to him.

Any other considerations I should be thinking of? Thanks y'all!