[Mike Andrew]

Do it! And, sooner than later as things can change very quickly and the opportunity lost. Either face to face or thru written word, your thoughts will likely mean a lot to them and some validation of their effects on others.
I did this a few years back with a somewhat older guy from the neighborhood who taught me a lot about working on cars by letting me hang around, ask questions and be a PITA. Rolled up to his house in the P car, identified myself and thanked him for the time he allowed me to hang around, the knowledge that he imparted and the car as the fruit of that. He was moved as was I.He did comment that I had made a better sports car choice than he had with his MGB which brought laughs from both of us.