@Johnny Corbett Generally the cash flow from multi family properties will allow for a greater return simply because of the efficiency and costs associated with purchasing say a duplex vs a sfr (obvious variables simplified).

My personal formula for critical mass is: My lifestyle overhead (variable for everyone) + 1 SFH deal per month = Critical MassThis basically means, if I can cover all my expenses and planned expenses in life & have the OPTION to buy 1 SFH home per month, I would consider that critical mass for myself.What is your personal formula?

I have used refinance by choice in recent times (fixed rate versus variable rate but typically the refinance loan has a higher cost) but maybe 5 years ago I looked for institutes that would provide an ELOC on non-owner occupied RE and I found a few but in excess of 90% did not offer the ELOC on non-owner occupied RE. 

Those with a variable mortgage (e.g. 5 year, 7 year etc) chances you are in the middle of a recession when the interest hike kicks in.

As there are so many variables for an old house, I decided to look for a new construction. 

Also, the heloc balance will be variable while the refi will be locked.

the variable in your expenses will be the mortgage payment. set the equation so that your revenue - expenses = $1,500. that will tell you how much of a mortgage you can afford to meet your cash flow goal, which will allow you to determine the purchase price.

  :)I think there is some value in what you are trying to establish however if I'm understanding it correctly, this sort of 'dynamic' variable that can be attached to occupancy stats to help close the gaps in inaccuracy. 

Throughout your time owning these properties there will be many variables that will cause a much larger swing to your bottom line than this. 

However, I did whey out all of the variables and I agree with the unanimous consensus, especially because the seller raised the price to 970k when I called to follow up.