I can tell you this- I winterized with the top off and took the front hose of the exhaust manifold and Nothing came out-I then took the rear hose of the exhaust manifold off where it exits the bottom of the hull (Inside the Back of the hull) and about 3 table spoons of water came out of the hose. Next I took the top exhaust hose off the water box and there was about 12 ounces of water in the water box because it took 3-4 turkey baster siphons to get it out.
I added about 12 ounces of antifreeze to the water box. NOW the water box holds about 2 gallons of liquid so if the small amount of water had frozen it just would have expanded slightly and would Not have been a problem.
Most old timers (Like me) remember the old 2 stroke days when Antifreeze through the engine and water box was mandatory because the engine was lake water cooled Not Sealed with antifreeze like our 4 strokes.