(If that is your objective)

You can research more about velocity banking and how it works, but my assessment is 1) it is a lot of effort for a minimal benefit (you can accomplish similar objectives using other principal paydown methods with less brain damage) 2) it likely no longer works effectively with today's interest rate environment because of the spread between HELOC rates and fixed primary residence rates. 

I'm much more objective about my investments, but a personal home has to "feel" like home.

@Brian Weber have you clearly defined your objective and criteria?

Always have a reserve because some surprise expense pops up with almost every property I purchase.The reason most Landlords fail is poor screening, no understanding of the law, and no policies or procedures in place to deal with problems swiftly, objectively, and in a business-like manner.

For a buy and hold your main objective is finding something in a desirable neighborhood and an area that is up and coming. 

The main objective of cashflow is for you to hold on to the property so you can exit (sell) at the right moment and make better gain via appreciation.  

We are all just giving you objective advice based on the information you presented us. 

Convergence of Private Money and Hard Money Industries: A Comprehensive AnalysisExecutive Summary:The private money and hard money industries, traditionally distinct in their approaches and objectives, have witnessed a remarkable convergence in recent years.

No system is perfect, so don't waste your time chasing after the next shiny object.