Hi HJ, thanks for the reply. My wife says I have ocd for even worrying about it..her attitude is the contractor will figure it out, but Murphy (as in Murphy's law) and me have sort of a relationship going on and you know how that goes.
Here is the disposal with measurements, 6 11/16" is the one I'm looking at.
http://www.insinkerator.com/pdfs/H538.pdf
Here is the sink, the disposal will be going on the smaller sink, I'm looking at the depth measurement of the smaller sink which is going to be around 7.5" from the bottom of the drain (underneath the sink).
http://tinyurl.com/9c83h
I measured as best as I could from under the sink in our kitchen and it appears that I have about 15" from the bottom of our current countertop to the top of the sewer drain. The house is about 35 years old so it's not ancient but it's not new either, not even sure this would affect where the drain was originally placed..
I talked to the place thats doing the job for us and they said that this is their most popular sink and they've never had a problem but that it's good to "measure twice and cut once." They also said something about a baffle that can be used on the disposal that would prevent water from coming back into it if it was lower than the drain..I'm not too comfy with this option.
There is a smaller sink that I know would work:
http://tinyurl.com/93j8a
But, it's smaller and of course the wife wants the bigger one.
The shop doing the work said they have a plumber on staff and they could always do what was mentioned, cut into the wall and lower the drain hole. Of course, I'm afraid that this will turn out to be one of those jobs where it's much more work than they originally thought.
Oh well...thanks again for all the info and any thoughts..
Steve