When it comes to rudder pull-pull, I am comfortable only when I use metal geared servo w/ 2 ball bearings. When the pull-pull is tight, it's very demanding on the output shaft and thus the gear immediately next to the shaft. For your Cap, I'd go w/ Hitec 5945 for great torque and speed. When I flick rudder back and forth using this servo, it seems like I can slap someone w/ the rudder.