Why go through all of this trouble?
Why are you going to all of this trouble? Indmar's instructions for winterizing the engine are to drain the block and manifolds and leave the plugs out. I do that plus drain the shower and heater, lubricate the threads so that they will not rust and have never had any problems. I get 2 or 3 good freezes each winter and store the boat outside. Not only is it just as fast if you are doing a total winterization but you do not have to dispose of any anti freeze. Even if it is biodegradable you can't just dump it into the lake.