mm43;
I haven't seen a schematic for the RTLU, but I suspect that a worm screw driven device creates a "feedback" position that inhibits hydraulic pressure to the operating rams beyond the set point. In this respect, the RTLU position is utilized by both port & starboard rams.
RTLU schematic below.
There are six "stops":
Rudder Pedal Stops - non-adjustable, which limit pedal maximum travel
Pedal Travel limitation unit - PTLU - limits maximum pedal command
Servocontrol input linkage fixed stop - limits masimum servocontrol command
Rudder travel Limitation Unit - limits the masimum input to the servo controls
Rudder Travel Stops - non-adjustable servocontrols stroke-end stops
Rudder Structural Stops - when servo controls are not installed
Note - There is no special stop between the rudder and the structure of the vertical stabilizer.
