Find Brandon's videos on YouTube for the "four square" method of analyzing homes and practice.

Additionally, they managed to refinance while the rates were at historical lows (and still somehow cashflow negative ik 😭), so any loan methods that involve changing those rates are not ideal.

Anthony,You would be surprised by using some old school methods like simply writing a letter like you mentioned. 

The 203K loan officers will allow up to 3 withdrawals on the loan. 

Each method has a cost in both time and money.  

I've done various methods and would be happy to connect and knowledge share if you are interested.

Would that method work again?

My interest are house flipping and the BRRRR method.

It isn't the metric you can talk about on a national scale, but if you keep buying the same product in the same area it is a very easy quick and dirty method to know how you are doing compared to other buys. 

And there is definitely ways to structure a sub to deal to protect yourself a little better as a buyer but the problem is and will always be that the lender isnt in the loop with this and can call the loan at any point which puts a lot of risk on the sellers willing to do this method and the buyers who are investing money into these deals.