When we are draining our bags, Admiral controls the switches at the helm. I stand on the swim platform. As the bags get less water (1/4 left in them) I gently lift the bow side and pull toward the stern so all the water runs to the drain line. This gets most of the water out. I think others have built a plywood style platform that has slope to it and put the bags on it.

I don't worry about what is left until the end of summer. Then I will disconnect the bags and drain and store.