Help Structure my Owner Finance deal PLEASE!

[Nick Versetto]

Have a seller that currently has a mortgage on a 2-flat that I'm interested in.  He's interested in working out the details of owner financing but want to make sure I give him one option and not 10.

Property is in Illinois

Sale price is 100k

Mortgage of 65k

Taxes 2600.00

I know the seller will have to hold a second but how should I straddle the first lien he already has in ILLINOIS?

I'd also like to use a servicing company to insure the existing mortgage is paid if you have a good one to use.