I have done it several ways. One is to join the metal pushrods near the servo with two wheel collars.

A second way is to use a wooden pushrod with two pieces of wire lashed to the end of it. You will have to make several bends in the wire to get outside the fuselage.

Third way is to join the two elevator halves with a dowel passing through the fuselage. The dowel must be in line with the hinge point. In this case, you only use one control horn and one pushrod.

Method one keeps the rods straight and slop free. Method three saves the weight of the second rod but is not quite as strong.

Tom