I have a Passagemaker Dinghy.  I spray a bit of silicone on the rudder fin bearing surfaces from time to time.  Nice and slick, but doesn't attract dirt or grit.  Daggerboard fits looser and seems to get enough water to make additional lubrication unnecessary.

.....Michael

   Speaking of the daggerboard, mine, on a Skerry, stays down, with a bungy cord through the handle and the ends made fast to the edge of the middle seat, but am having problems with water coming up, during a reach.  The water comes up in between a small space between the bottom of the daggerboard handle, and the top of the daggerboard well and then spills out slowly onto the boat bottom.  Not in great quantities but enough to be an annoyance

So I've thought to take an old bicycle tire, cut open, and wrapped a few times around the daggerboard, just below the handle.  The idea of course is that it'd make some kind of waterproof gasket.  So I've put one on it, but haven't tried it out yet.

Anyone know of any other ways to keep the water out? 

- Brad

If by "experienced" you mean "built and sailed one NE Dory" then I'll say we just followed the instructions. No lubricants. We have the optional kick-up rudder and we ended up having to sand off layers of epoxy and redo it because it was just to fat for the case. Once we got that right it works perfectly, never kicks up unless beaching.