Owner financing options

[BJ Ross]

Looking for advice on options to present for owner financing. Seller has presented two options:

3k down / 800 per month

5k down / 500 per month

Asking price 58k

3 bdrm/1 bath near campus

Seller has said they could very flexible on terms. I believe I could rent for 900/month looking at the area. Is my best option to present amortization schedule over 30 years w/no balloon payment? What factors are critical to making the deal work for me along with hopefully a higher acceptance rate from seller?