Finally got it done. This is my dual elevator setup.

Each servo is equi distant from elevator control horns, but the servos are not back to back cause if you do use the servo space provided each servo would be half way out, so I cant understand why there are two space for back-to-back. So I cut a servo slot so that one servo lies on top of the other.

In doing so you have to close up one of the original servo space provided and re-inforce otherwise the this end of the fuselage may snap ! I re-inforced it with peaces of carbon fibre stips.

Rudder is then pull pull. Note in pictures that I was lucky that cable just cleared out of elevator servo