Even less if splitting the lots costs any real money. 

I don't have the 10% for the down but thinking of using a HELOC to get the money and then add it into the calculator.

You still have to pay that money back.

I don’t have a loan on the property and hold it cash, but, if I sell it would lend the profits as hard money and earn 10%+. 

Same day auctions of course are not going to be possible for a lender to lend on the initial purchase but you can often get the same hard money purchase terms right after closing if you're able to buy in cash

We have made money buying properety based on cash flow (lower priced) rented out for a period, then selling to an owner occupant. 

That being said due to the number of sharks out there I would only spend money that I can afford to lose. 

Keep saving money. 

Be prepared to spend a lot of money creating the infrastructure.  

As mentioned before, you can get away with paying for the draw money, but not using it.