Need advice on Selling Land with owner financing

I bought 20 acres on a very busy road in a growing area of Houston, I felt like it had great potential as a commercial property. It is very close to the Highway 99 that loops around Houston. The property needed some clearing and major clean up/demolition of some old buildings and junk from the previous owner. I've finished all of the clean up and just put the property on the market for $325,000.00. 

I like the idea of offering owner financing as an option because:

1) cash flow

2) It allows me to be more creative and flexible with a potential buyer.

I had a business owner contact me today about buying all or part of the land, and I mentioned owner financing was a possibility. (Did some research and his business is legit)

I'm thinking my terms for owner financing will depend on the offer:

For instance if its close to asking I'm thinking 10% down and 7-8% 15-20 years

Or if its lower but still accceptable I'm thinking 20-25% down and 7-8% over 15-20 years

I have $50k invested in the property and owe 175k.

Anybody got any advice? Good? Bad? Do you have another Idea?