It's not rocket science maynge.

I happily laid my neck on that chopping block by giving market forecasts (some may call this predictions, but a prediction is a guess, I do forecasts which are rooted in the SCIENCE of math and data to project out future-casts). 

Don't reinvent the wheel, just follow proven building science and you won't go wrong.http://www.tcnatile.com/handbook-all/910-2014-tcna-handbook-for-ceramic-glass-and-stone-tile-installation.html

Is there any science involved or is it all plugged into a computer and it spits out the appraisal?

Not sure if you've run a marathon, but what I've found (and what the science tells us) is that the further you go over a marathon, the less like a marathon it becomes - mostly because the predictive value of VO2 Max breaks down and there hasn't been a good alternative developed to predict times. 

I find this fascinating.

Like you, my fascination is in mini storage's but unfortunately they are highly capital intensive but can pay nice dividends with low maintenance.

I find this all fascinating, but a bit overwhelming.

It's not rocket science, just takes discipline to follow the principles and action to find the deals and close on them.

Not by 20% or anything, but it's not an exact science and they are flat out wrong on occasion.