Mitch,
The rudder and stuffingbox/driveshaft are both treated about the same. Either some type of grease/oil, and/or maybe a small 'O' ring at the top under the control arm. If the top of the rudder tube is below the water line there will be some leakage unless something is done to prevent it (back to the oil/grease/'O' ring thingys). There can be leakage even if the tube extends above the water line due to the water flow from the prop. Same answer as before. As long as you don't cause the servo(s) too much additional 'work' you can go about sealing a rudder tube any way you want or can think of. A small bit of water isn't very threatening if you remove it. More than a little bit means something should be done.
- 'Doc

PS - It's a 'known' fact that scantily clad ladies, wearing hula skirts, dancing around your boat will 'cure' the problem. If you resort to this method, please post pictures.