MPBC,
Anything other than follicular units is outdated. I wouldn't consider doing any more minigrafting. Regarding major shock loss, how much of your original hair do you have left? I wouldn't think you have much of your original hair left after four transplants. You shouldn't experience much shock loss to your transplanted hair.
As Laughter's Medicine stated, geographic location shouldn't play a major role in your decision, however, there are some very fine physicians in the New York City area. Dr. Bernstein, Dr. Epstein, and Dr. True are all in the New York City area and all come highly recommended on this site. It is always wise to have more than one consult. With that being said, Hasson and Wong have a very good reputation, so you are off to a good start.
GuitarPlayer