My credit is excellent, but still went with FHA for the lower rate at 6.5%.

I'm creating an excel sheet to help calculate whether properties are more or less likely to be profitable for STR.

I've never been to Milwaukee but I know how to search for rent properties.Consider these likely candidates:  https://www.realtor.com/reales...

Then visit the NARPM website to find an excellent PM company in your area.

I have a track on a house that is a good flip candidate - 2 Br, I Ba, 70+ year old structure with a strong foundation and good systems, sitting on 1/3 acre at the end of a cul de sac.

My CPA connections unfortunately are focused in Southern California, but you should reach out to @Michael Plaks on this site, who is based in TX and is an excellent resource for investors (https://www.biggerpockets.com/...).

Why not check out the excellent response that @ Nathan Gesner offers almost weekly to folks on this forum that ask this same question.

Find a good mortgage broker and ask them to help you understand your different loan options, and the advantages/disadvantages of each (a good mortgage broker will be happy to help you with that, and can also help you understand why you qualify for certain amounts, and what you'd need to do to qualify for different amounts).House hack a property every year until you hit your limit of conventional mortgages (usually 10), and you can build up a pretty excellent portfolio of RE in ten years--especially if you do thorough analyses, thorough due diligence, and buy the right properties in the right areas!

I love the financing, still historically excellent terms and a nice rate. 

Use Excel STR proforma template or variations of this.