OUCH! I found an issue. The rudder horn on the left side is longer than the one on the right side. Regardless of where the pivot point is on the servo, left rudder always ends up in more slack.

The hole in the rudder horn on the left side of the plane is 1" from the rudder, while the hole on the right side is 3/4" from the rudder. The rudder horn is one piece that slides through the rudder and is epoxied in place.

What I see my options as being are:
1) Drill a new hole at the 3/4" mark on the left side, trying to keep the hole the same distance fore or aft of the hinge line. My question here is about uncertainty of PC board strenght, drilling, and plugging the old hole.

2) Cut off the existing horn and try a new style. Issue here is the existing cuts and parts epoxied in the rudder either being in the way or weakening the attachment point.

3) Somehow modifying either the servo horn or adding some kind of tensioning device.

I like option 1 but would like to hear some comments (especially on drilling and plugging holes in PC board horns 1/4" apart).