There is no 'per square foot' method that is accurate....At least until you have quite done a few.... 

But I am so intrigued with the BRRRR method just not sure this is the one for that.

If LL uses accrual method, they can book revenue without receiving.  

Strategies like house hacking, the BRRRR method, and long-term rentals have worked well for me.

You need to set a deadline for them to correct the issue, then follow up with an inspection or other method to confirm compliance.

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.

Sorry for the questions just curious about your method since it seems different than most.  

They really do not know how to decipher what is a question posed to get business, then they end up with an inbox full of DMs.A lot of us have started using the "nice" call-out method, which involves responding something like, "I see you are an agent in Dayton asking a question about housing in Dayton. 

Given your situation, one strategy that could work really well for you is the BRRRR method (Buy, Rehab, Rent, Refinance, Repeat). 

that was not a method that Armando taught in the seminars I attended these were strickly how to find BRRR props and rehab them and then resell or refi and keep.. the Markets we worked were Vegas and Orlando and Frankly those investors who actually bought property doubled their money or more with the deals i funded for them and they bought on their own it was 2011 to 2013 which as we know was a prime buying time and had to hand it to Armando he picked two of the best Markets..