If you measure yourself they should come out and complete the install in a few hours. 

It takes a few hours to measure, look at product and price materials.

You should be confirming all the key elements of their application by phone or other measures that verify the information in their application is true.3) Get a good lease, legal in your state, that protects you as much as possible, particularly if you are in CA, which it appears you are. 

(measure twice, cut once) ;) Are you doing all the work or subbing it out?

Cap isn't a good measure of the return you'll receive especially since you use leverage (which is by design but often missed by most investors).  4.

You might look into some sort of measuring system for the heat.  

Like any marketing campaign, your ability to stick with a consistent plan and measure the results are key ingredients for success.  

We ended up measuring everything ourselves (paid Lowes $70 just to see what their pro measuring serve has to offer and it was an absolute garbage as all was inaccurate).

I feel there should be some kind of additional measure put in place to weed out many of these realtors prior to them being "realtor certified".

One of my favorite measures in making this type of decision is return on equity.