In my opinion, here is Jim's most important point and why you really don't need to worry about it much:

"However, it's not all bad. The water rudder SHOULD NOT be in the water except when you are taxiing slowly. Once you are up on-step, it should be high and dry, and it shouldn't matter which float it's on."

I have one set of floats with an Ernst rudder, and another with a very similar type. I leave the little rubber band OFF, for the above stated reason.