Subtracting the $1600 leaves $700 of profit with each new house.

Unfortunately  alot of the renters treat it like a rental car and leave it with significant depreciation.  

The key is if someone is lending from a SDIRA to leave reserves in case the borrower defaults.  

If they are leaving mid-Feb and willing to pay 6 weeks' rent to break the lease, that is reasonable. 

Let’s leave the magic to the magicians 

Hmm, what didn't you leave out?

Like you we had 3 teams of two door knockers  2 for safety one women one man.. and we door knocked every NOD in our 2 mil MSA  all to boil it down to if we were very lucky to get 2 to 3 deals a month.. now we were a little different I only would buy very high equity deals.. and we leased back .. because as you state 99% don't want to leave.. 

Second, I let the tenant know I know their criminal history and tell them to leave.

This is the first home that I am landlording and the first tenant was amazing, I was sad to see her leave but happy because of the reason she left was a good one.I am looking for advice from you seasoned pros! 

Number 2, a lot of wholesalers forget that building a business is a long-term thing and they get greedy leaving no room left in the deal, #3, make sure you've disclosed evertything to all parties.