If I'm reading your first post correctly the elevator pushrod is a single wooden dowel with the metal rods in a Y to the individual elevator halves. Have a Modeltech Sukhoi that was set up the same (keyword - was). The dowel was not guided or restrained and under load it would always snap to one side increasing the throw on one elevator half and decreasing it on the other. Loads of fun. Trashed the pushrod, put two servo's in the tail, no more problems.

Mike