Typically there are levels of zoning due to density and block construction type all in a city general plan.

My guess is it was determined that nothing in the immediate area was a good comp due to age and finish level, so the appraiser ventured farther out for comps. 

Note this is the appreciation level of my worse property that was worth ~20% of today's values. 

The best skip traces produces data at the credit bureau level.

Land owner got suspicious when top level water tank was built on 10th floor.

I'm suggesting you avoid Fortune Builders $25k level, but local boot camps by your REiA maybe $499, even $999. 

That being said, I am sure that building from the ground up is another level and I am setting myself for lots of headaches but hey, I gotta learn somehow. 

I consider the type of care that needs to be taken to avoid fraudulent investments in a self-directed retirement account to be on par with the level of care needed to avoid fraudulent investments with non-retirement money.As for self-dealing, you are correct that these accounts are for your benefit later on (presumably in retirement).

Your main role is to ensure that the level of stuff is not causing maintenance issues and that you can get access when you need it. 

Check out the book, the Flipping Blueprint it can give you some guidance on flipping estimates, it depends on the level of rehab there are some rough numbers once can use as a price per sqft.