First time investor- Duplex-seller financing- NEED ADVICE

[Jennifer Jump]

Hi BP Fam, just made an offer on my first investment property. NEED HELP! Multi-Family 3/1 down and 3/1 up. $350,000 listed by the owner. Sitting on the market for over 100 days. After doing research duplex market value is roughly 280,000$. My offer was to do seller financing at the 350,000 with a chunk of money down and payments to the seller for 10years. He’s willing to negotiating and I’m assuming going to counter. Listening to you all seller finance is the way to go but I’m not sure how to run the numbers. The house is way over valued but assuming the renters are going to pay the payments. How do you even run numbers on a seller finance deal😬. Their is a minimal amount of cash flow to nearly none at the worst case scenario if you figure property taxes, cap Ex, etc… Their is oppurtunity in the attic to turn into a studio 1 bedroom with kitchen and bathroom. Huge expense. Not sure how much it would cost, but would add $800-$1000/mo. Another thing I’m wondering is do you get title on a seller finance deal? What are the things I need to include in the deal? Can you cash out refinance after a certain amount of time so I can pull money out and put it into another. Any advice would help. Thank you!