In this case, it is not.It's about intelligence and data, not "patience and Persistence".If you need to "follow up" on people, it means you are not reaching motivated sellers.

Hey everyone, I’m working on a platform concept called RentKeep that focuses on providing property intelligence to help property managers make data-driven decisions to increase their NOI.

I once downloaded and analyzed Zillow data to find markets with attractive cap rates...

Work 20 hours a week at McDonalds and you can earn an extra $1,000 a month.

The data should be transparent so you can verify what supporting data was pulled.If you worked with our brokerage. 

What data do you gather and what tools do you use to optimize this process?

Do you need a bigger truck and a trailer, extra insurance storage..can you rent your machine out when your not using it?

Just get a loan broker residing in Cincinnati, pay the extra origination cost (those fees are usually buried in a lender's origination fee anyway) and find the right lender for your situation.

Is anyone aware of a good data sheet that provides some basis for OpEx?

With your construction background and the extra time your day job gives you, you're in a great position to dive into real estate investing.