RE: First floats
I have done both. These days I think it's most practical to run a separate servo on the float. The long flex line off the rudder servo always looked kind of silly to me. If you use a small servo, it will weigh less than the linkage. Just take it apart, brush the motor, pot, circuit board with Corrosion X, put a little grease on the output shaft and seal it back up. You only really need a water rudder on one side. Weigh both floats and put it on the light one.