And I can't really sell at the moment because I don't have anywhere else to go.For the record, I don't want a HELOC because that's not guaranteed money if the bank decides to pull/reduce the line.Lastly, is there any truth (benefit) to having a higher mortgage payment on a rental and thus less profit to report, which equates to better tax treatment, or is it that just nonsense?

Plenty of people do invest out of the area, but I think that adds an extra element of risk into the equation.

What's the equation I use to figure out my Max Out Of Pocket I can give them and monthly payment?

Identifying passive investors with money to lend or invest is the easist part of the,e equation.

In the long run I see the better issuers using their own technology and marketing systems to attract investment dollars using the issuer exemption and the platforms and portals being eliminated from the equation entirely.  

As it stands now, the pre-approval from the credit union says I'm approved for a $540,000 purchase price on a house (again we didn’t know the value of this house at that time) which equates to a $430,000 loan after my 20% downpayment.

I wouldn't worry too much about not having assets when it comes to qualifying for a mortgage, that's doesn't factor into the equation, with some readily available conventional loans.  

Typically, investors are looking for long-term buy and hold, so the cash flow part of the equation is more important than the appreciaiton.

I was able to find a couple contractors who saw the benefit of working for me year-round (at a fixed rate), but the rest of them wouldn't come off their market rates in the summer months, so they only worked for me during the winter (at about 1/3 of summer rates, because they were all fighting for the work).Again, that's certainly their prerogative, and it's not my decision what they charge or how they run their business, but it meant that volume didn't play into the equation. 

Also, there aren't equations to predict unexpected life events and so I would always shoot much higher than you think you need.