I have no idea what their methodology is, but generally speaking it looks reasonable to me! 

Just an FYI - We are presenting on the BRRRR methodology / topic this coming next monthly meetup.

For details on our data sources and how we put all the information together to create our final rankings, read the Data and Methodology section below.2.

We are building a portfolio of rentals and I am looking for a strategic methodology that can be applied to all new rentals that covers everything that is addressed prior to tenancy.

The IRS' preferred methodology for a study is engineering-based, done by a licensed engineer and an expert in construction.

Unless you like spending time with auditors, I highly suggest only using the IRS' preferred methodology, an "engineering-based" study.

Does this sound logical, should we follow a different methodology?

Even if units are vacant the appraiser, in complying with rules of the Appraisal Institute, will use comp rents to arrive at a likely rental rate for the vacant units, unless their is no demand for those units as rentals or the cost of getting the vacant units in condition to rent is greater than the net present value of the income stream they will produce.In any case, without going deep into methodology, MAI appraisers will determine if the demand exists for renting the vacant properties.

If we were to use existing HELOC funds, then it’s just up to how much mortgage rates change in the 6-12 months we’d have to wait to re fi.To your point, if we can do REALLY well on the BRRRR methodology, I’d rather be efficient in terms of aligning with our long term strategy, and it sounds like we might be able to do that if we choose carefully.

The notion that Dave Ramsey's advice is for the poor or middle class is a fair argument in his methodology for real estate investing but when it comes to the tried and true staying out of bad debt and sticking to a budget; he could not be more spot on for anyone.