Cash flow is simply does the money coming in equal more than the money going out, including  reserves?  

Where people get in trouble is when they look at it as a pay day and put the money in the bank to pay for bad debt, trips, cars, bills etc...Use your cash flow to pay for these things, after you have some reserves!  

.- Strategy/Financing = As mentioned before, I want the cash reserves we have now to be mostly what we use to reinvest in future properties and have a generally self-sustaining model.  

AU takes into consideration the front end and back end ratios, credit score, reserve assets, and other factors. 

I'm a part time investor and bought house number three in June and I've been working towards creating a solid financial picture for banks to get traditional financing for a fourth buy and hold deal: paying down debt, saving six months reserves, filing taxes to show rental income to lower DTI,  and rehabbing (Higher HELOC appraisal)  It's been pretty quiet on my real estate front and I've been wondering if I should be more active trying to acquire house four through creative financing, or mailing yellow letters?

That right is reserved for the owner of the property only.  

You can check out long term historical price trends for different cities to confirm this. 

He said the last downturn wiped out a lot of folks due to the lack of reserves.

Wow, sounds like a great way to get into a house for nothing, while keeping some powder dry on the side @Brian Volland.The only other thing that might be a useful metric would be to do present value calculations on the portion of cash flow that you would effectively hold in reserve for future CapEx, rainy day funds, etc.

But I still do not have confirmed measuments.