There's more than one way to skin a cat.
I guess it just depends how ingenious one wants to get. Ball link makes sense. One could use the original RO torque rod and mount servo in a manner to move it similar to the old RO escapements or magnetic pulse actuators. One could maneuver a flex link to alignment is more true. Use pull-pull cables. Mount servo below rudder to directly torque it.
I've use the pushrod through the back fuselage plate's torque rod hole, bent up and forward to the nylon control horn ala Carl Goldberg style. (See OuterZone Goldberg 1/2-A Skylane plan servo detail found on: http://www.outerzone.co.uk/plan_details.asp?ID=868
That probably provides the longest pushrod and is more tolerant to flexing.