There was nothing quite right for me on the market that was light, maneuverable, waterproof, and comfortably breathable for long periods of time both in the cockpit and around seaplanes, so of course had to invent something:
I selected a popular "splash jacket" of lightweight, waterproof, breathable material that has quickly adjustable Velcro seals at the wrists, neck and a tight, draw cord waist. To beat condensation wetness inside the jacket from the moisture overload from sweat when exertion overwhelms the water vapor permeability rate per square inch of the high tech material, I had my tailor sew some full length, water resistant zippers from each wrist to high arm area, one horizontal zipper across high chest area, and another horizontal zipper across high back area with a long enough zipper-tab cord to be self zipped. Separate pants of the same material with quick adjust, tight, velcro seals have zippers that run diagonally from each lateral ankle area to above the crotch area.
This system allows the pilot to remain fully seated with a 4 point shoulder harness on, with the suit system on and to open all zippers quickly without leaving the seat in order to vent both body heat and body vapor before it forms significant sweat plus also, to access pockets of clothes as the suit has no pockets save for one small, left arm pocket. All of the arms can be exposed, plus the chest and back cross-ventilation. Most of the legs can be exposed. I may have a hood added of the same light weight breathable material but, for now use a standard detachable wetsuit hood that can be pulled back and still be readily deployed at any time including in the water.
Did the tops in both 2XL size and for colder weather with more clothes underneath, a 3XL size. I consider this essentially a "Thermal-Shock Reduction System" for personal survival enhancement in cold water immersion. If the zippers and the velcro seals are all tight prior to immersion in frigid water, it can only enter very slowly and the suit also functions as raingear....