Neoprene survival suits are generally made in the "one size fits all large persons" mode. They are too big and uncomfortable for any person smaller than XXL. They are also too bulky for the general aviation cockpit. I have a diver's dry suit that, except for the tight gasket at the neck, is quite comfortable to wear and which, combined with insulation, booties, gloves, and neoprene cowl, should provide protection equal to, or greater than that of the survival suit. I have not asked the "authorities" whether such a rig would be legal for over water flight. Nor have I seen any data comparing such a combination with the standard survival suit. Any comments, criticisms, etc?