Lenders, is this truly an option and if so, what are down payment percentages and interest rates you're seeing?

Because a large percentage of the charges are base fees that do not change based on use!

Some have flat rates, some have percentages, eviction coverage, etc. 

The local HML can usually pull the trigger much faster than an outside person does because more research has to be completed to asses risk in lending for that area.This is why local HML lenders rates might be lower than a national HML lender that prices a few percentage point higher and one to two points more to price in the unknown factor of the area.

In the words of famed real estate mogul / investor Barbara Corcoran:"If rates go down just another percentage point, that's what I'm hoping for by year-end, prices are going to go through the roof...Everyone will come out and buy.

According to Core Logic (a reliable source), Ohio has the 4th lowest percentage of investor RE. 

The question is how do you spring a large percentage increase on your tenants without them leaving?

Going into a potential deal, I look at the track record of appreciation (sales comps) in the immediate area, not the general area, and based solely on properties that are within 10% higher/lower in sq ftg than the property I'm looking at.I have a goal of a specific number ()in dollars, NOT percentages) that I need to achieve in appreciation. 

Is there a percentage to respect ? 

The better the terms the higher that percentage could become.