Dan,
I have to fall back on the CH-53A as a basic design point. It was designed as a 33,000 lb. machine with a six bladed 72 ft. diameter rotor. Anyone with experience in one of these machines will admit that it was fine aircraft. That combination resulted in a fast smooth machine with an abundance of growth potential. Using similar criteria for the S-92, I believe that a five or six bladed system with a rotor diameter similar to the S-61 would be a great starting point.