Besides this, my wish is to not need to wake up every morning with alarm clock, neither to work for requested quantity of hours per day, nor to be at X place on exact Y time.

The quantity of sales? 

From what I have been able to tell, 15+ year old inventory is limited in quantity and listings, is this true?

An excellent merger of expectations-- quantity, and quality.

I found one of the most respected traders for that market and signed a deal to buy some small quantity from him (I didn't make much money on that trade :) ).

Using my strategy, I can do a lot more quantity of deals.

Quality over quantity. 

I respected the seller's choice, even though I lost money on the cost of my Phase I, because the law requires that if, at any point, it is determined that a reportable quantity had been spilled, the consultant doing the Phase II HAS to report it to DEC, regardless of who has hired the consultant.  

So I am a little bit uncomfortable making the deal with a tenant who is pretty much an unknown quantity, at least from my perspective.  

Seriously, though, it is more about quality than quantity for me.