Is it as easy as estimating ARV through comparable sales, or should I downward revise ARV ~10% to be conservative?

the bright side of finding BP after you've already had a deal is that you can focus and have a frame if reference for the info you get, compared to your previous experiences.

Two of our contractors spring to mind, the plumber who despite all the best connections in the world hates the business of rental property, and our tree guy who plays the same game as us (buy and hold) and we often compare notes.Some people like the game, some don't.And again, the debt thing is down to personal choice, although interestingly a friend who spent $65k on a truck has since told us that it's the last time he's buying such an expensive item, and when it's paid off, it's paid off.

I personally believe that IRR is a far superior metric compared to commonly used real estate metrics like cash flow, CAP rate, and cash on cash.  

You need to look at warehouse comparables in the area listed for sale and solds to get a cost per sq ft.  

Consider vacancy rates and look at the historical appreciation of rent in the area.In Canada very few markets support good cash flow comparable to the United States, but we still have thousands of very successful investors who make due in every market.Do what's best for your future.

I thought with the beautiful reno and the price per foot I was asking compared to all the comps that it was a total win.

The money you spend on doing this might be recovered in one or two years compared to the increased insurance premium.  

Also, dont under estimate the value of picking out the design elements of the house.

So get to know the prices in the area that you are looking at and run those numbers comparing the local rents.