Why not try this: Split the elevstor halves as designed. Set up a tiller bar driven via a short wire rod, located just behind the elevator servo, which needs to be a "large" one, maybe 100 oz-in or so. Then connect pull-pull (closed loop) wires, 2 on one side to both elevator tops and the 2 on the other side to the bottom of both.

Run the wires thru the covering at the tail through fabric grommets. That'll make it look just like the full size plane.

Lots of adjustments, but very sturdy and a lot less weight than 2 servos plus a reverser plus 2 pushrods. Less chance of problems too.