I agree with the supposition that 100% occupancy reflects leaving some money on the table.

The last thing you want is for this thing to land on a lawyer's table.

We started out too low and were leaving thousands of dollars on the table.

I’m going to put together an amortization table to get a better picture!

People keep telling themselves this to console failure.90% of the population were active internet users in 2018.By now.. look at the trend it is more like 95%+?

Whatever deal they had is not legal and I don't know what the section 8 will do to you if you continue accepting cash under table, also irs may not like it.It is so hard to get a voucher for section 8, so I don't think the renter will give you hard time especially knowing she might loose her voucher for paying cash the previous landlord or to you.

.), what if any income it's generating, and what skills you bring to the table, since that'll also dictate what/if any kind of loan you can get.

Finding a deal below market and acting as a wholesaler could be the value you bring to the table. 

If you don't have a quote from a lender, as a back of the napkin way of estimating how much cash you will need to bring to the table, I suggest using 30%.

Doing it Leon Johnson style with "Now I'm going to get real personal now, if I brought that $650k in cash in a brown paper bag, and set it on the table, what would you do with the money?"