I've just started this year and am finding the MLS increasingly difficult to find anything that pencils out for a long term rental.

The plan is to increase to market after 6 months.  

If they're 10 year tenants, you might have an opportunity to increase rents as well! 

We had our second home rented out before the closing.At this point and after reading numerous books on real estate, I realized that although we had reached our goal of owning a rental, our finances were completely vertical and I need to spread out to increase cash flow and reduce the impact of a vacant property.In January 2016, I started data basing different markets across the USA.

Welcome @Joel Schilperoort.Where are the properties you sell/buy for yoru customers?

Aggregating data from public information is typically better to buy or rent from commercial providers unless you want customized data fields, highly targeted leads, compiled lists or response lists (prospects test have responded to others' offers). 

Also, any potential pay increases, windfalls, inheritances, etc are not included.

However, be careful you properly forecast for increases in the property taxes.  

So take your estimate and increase it by 10 or 20%.You don't want to invest in thin deals especially with an HML lender.

Large luxury apartment complexes have been built over the years around the area meaning the rental business is increasing.