I'll add that the snap dragon pogies are literally the only ones that I can fit my hands into, and I'm only about 6' tall.
I couldn't find them in stores once after I lost one and needed to buy a new set, so I bought the largest ones I could find in the store, which were the IR pogies. They seemed like they would work in the store, but I couldn't get my hands into them on the river when they were wet. I've tried the bomber gear ones, too, and had the same problem. I don't know if I have abnormally large hands (I don't think so), but I think size is really only important factor with pogies because they are all made with neoprene and velcro as far as I'm aware.
And if you think about it, they mainly work just by limiting evaporative cooling by keeping the wind off of your hands.