Sub to creative financing help

[Michelle Melendez]

Hi, I'm new to the sub to world. I have a friend that is willing to sub to. He owes 220,000 and could sell for about 410,000.Every sub to deal example I find does not have this much equity. He's at a 3.2% interest rate. We talked about 100,000 cash for him but I would have to finance 80,000 of that.  My payments would end up being about 200 over the rental rate. Any thoughts?  Thanks in advance!