Encan

If you notice the servos moving on the foam tape that indicates there is friction or restricted movement. Check the surface hinges for limited travel and check the controls for friction. Basically you should be able to unmount the pushrod and reach in with your fingers and move the controls at least as far as the servo does with extremely little resistance. Try to hold the end of the pushrod very close to where it sits when on the servo so you sense any binding that the servo will see.

As for me I'm a traditionalist. Grommets and screws forever..