Sorry for the delayed reply. Itīs been a while since I logged in here on RCU. My solution was servo locations easy accessable at the front portion of the rear fuselage. One servo for the rudder and one for each of the elevators halves. I used carbon fiber tubes for the pushrods.
My Shrike was later sold fo the aircraft company "Wermlandsflyg" in Sweden for display purposes. They have a few Commanders in their fleet
https://www.wermlandsflyg.se/v%C3%A5ra-flygplan

Leo, do you still have the Palmer plans Shrike Commander?

Is it your opinion the horizontal stabilizer structure is sufficiently thick for a standard size servo to fit within the horizontal stab (servo mounted to a 1.5mm plywood plate - servo laying on it's side), one each to control each of the elevators?