I’m funding my first private loan this Monday.

Then apply the first funds to the repairs and give notice to quit or pay if they do not pay in full.

For the first year, save all "cash flow" in a dedicated account and ensure you keep it there for your emergency fund.

I have fund hundreds if not thousands of deals that have been brought by OREO brokers  or brokers who choose to work distressed assets.. 

Have you considered doing a 203k so that the repair funds are wrapped into the loan? 

., they will get a pay off from your lender and disburse funds to them from the sales proceeds....you never see or receive that money.

There are some limitations compared to 'borrowing' from a SOLO401K, but it does let you put 100% (or close) of your funds to work. 

The plan currently is to fund this flip (price at foreclosure sale + reno) by private money at a 10% interest rate with no payments until closing, after the flip.I looked through all the contracts available here on BP and none of them seemed like the right fit. 

Most new investors I am gathering have the same issue - they have learned about how to make a deal but don't have the funds.

Every market is completely unique and the prices for materials, labor, permits, etc... will vary somewhat from place to place, so you're probably not going to get a really precise answer on this one, but I'll try to point you in the right direction.The number 1 rule is spend less than what you can sell for, while still having a marketable and desirable property that will generate a profit.