For example, in Georgia, it would be very difficult to find a broker who'd be willing to allow us to use a non-state contract and not run the deal through the brokerage (state laws are pretty tough on brokers and as such, brokers are tough on agents).For the most part, we work with flat fee brokerages, so we're only paying a small fixed fee every time we do a transaction (not a percentage of the commission). 

(b) I calculated the break-even point when I was buying - - what percentage of occupancy was required to pay ALL the bills.

It'd probably be a percentage point higher than traditional HELOC, somewhere between 5.5 and 6.5%. 

My question is, when purchasing a SFH, does anyone look at the percentage of Home Owners vs Renters for a given zipcode?  

Rate, terms etc.If I were using a HELOC, I would factor in the draw and the percentage I am being charged to include in the property deal that I am also financing, if I am financing.

How do you factor in taxes and worker comp insurance premium figures when you say at cost, do you and the investor have a fixed percentage or do you give him a breakdown every week or so.

All deals are a little different based on what it is you're trying to accomplish with the loan and with the property value and rehab looks like however you have to really question if your percentage with the private lender or investor means you have to give up some of your profit.

What is the recommended percentage you should put down to be conservative, not over extend yourself, ensuring good probability of no financing hiccups?

Well as a percentage amount it is high, but as a dollar amount it is not high.However the size of an EMD is not entirely without risk.

 $100 per property could be a good deal or  bad deal - typically PMs take a percentage of rent, so if these are very high rent properties, then $100 is cheap.