If you oversimplify it and take your total cost to close the deal / monthly savings = # of months to Break Even.

Before you decide to pull the trigger with any Bank/Lender make sure the they are well versed in DSCR guide lines and close more than a couple a month. 

This month we have placed three opportunities with investors looking to balance their portfolio.

My suggestion is to build a spreadsheet and include the net cash flow to you for every month of the deal, then use the IRR function to figure out your return. 

My second question is do I get a more energy efficient and raise rents but now include heat in their monthly rent?

Is there a place where I can type in the address of the properties I am considering, and it will spit out an estimated monthly rent? 

We send countless emails, and he answers us every 6/8 months saying he will work out a payment plan.

Up until then I was cheerleading the earlier thought experiments about supporting lean/regular/fat income with ~$1000 / month per paid off SFH, thinking “I could bang that out in 5 years”.

You could arrange payments with them (eg $1K a month for the next year with interest).

You have a personal issue- car engine blows up, so you tell your tenant that they need to pay double the rent for one month so that you can get your car fixed?