Good comments, Mr. Paine
One more minor addition that I might add: The servo pendulum vanes that I have used, seem to work fine with a "normal" distance of 18 inches from tiller post to steering lines attachment point on the tiller. However, I found that there are times when this tiller attachment point could stand a change under certain conditions. If the attachment distance were shortened, the rudder would achieve a greater steering angle as the lines from the pendulum pulled the tiller over. Conversely, if less rudder swing were desired, the tiller attachment point could be moved farther from the rudder post. Might be better in lite air? Anyway, experimentation will possibly improve one's experience with the vane steering. I added a 12" piece of genoa track to my tiller, with the steering lines led to a "car" which could be moved fore and aft on the tiller. Thus, I am able to vary the attachment in an attempt to improve my vane's performance in varying wind and sea conditions. This is sort of "guilding the lily", perhaps, but it's fun to experiment. In another vein, pun intended, I do not feel that servo pendulum vanes and wheel steering are very compatible. The vane might only provide 6 inches of movement P & S at the tiller, which will give the rudder a good swing. Turning the wheel attachment drum 6 inches along its circumference will not swing the rudder nearly as far. It will generally steer fine up wind, but "run out of rudder" when used downwind. This may not be a problem with all boats, but I know it is with many wheel steering installations.