Bottom line, it is unethical and short sighted to tie up property when have little chance of closing the deal.

Once you have accumulated the necessary 20% equity in the property, whether through principle-pay-down, forced or natural appreciation, or a combination of multiple factors, you would then seek to refinance to a conventional loan with the 20% down payment already built into the property.

Then after the 10 years, I'd pay the principle?

The principles don't change; only the interest rates do.Sure, this particular strategy was more attractive to borowers back then when interest rates were through the roof. doesn't mean it does not work now in certain situations.

I used the years worth of rent and applied it to the principle only on the mortgage.

Best to do these things at the same time to hit more than one of their senses at a time (smell & sight, in this case) so the message to relocate is clear. 

Just finished Principles: Life and Work by Ray Dalio.

Here are some of mine:Law of SuccessThink and Grow RichRichest Man in Babylon7 Habits of Highly Effective People 4 Hour Workweek The One Thing The E Myth PsychocyberneticsAnd how we can teach how we utilize these principles in our businesses, so that other can utilize the same principles in their businesses

I think the majority of people on this sight are observers and learners waiting for the right moment to jump in (or more often times not).

Once I hit the point where I have run 40-50 units, I would feel more comfortable becoming the principle in a larger transaction.