Could you use a brass bar.
Glue up a base for the brass, mount the the brass with a bushing to the base. Run control rods from the Servo to the brass bar. Then from both outer edges of the brass bar connect your pull pull links and run them out to your control horns. Use two 1/4 scale T horns on the control surface, match them back to back instead of using the back plate.
Am I on the right track