i usually glue the jacket to all the formers.
i also run the steel rod as long as possiable on both ends if use with nylon.

thicker guage steel rods ?

the rod must be allow to shift some what when throw is apply.
servo buzzing tells me i have too much throw or binding.

what I've notice are the play between the horns and cleves.
the cleves pins od are smaller than the horns holes.
hold the rods stationary and wiggle the control surfaces.
i up grade with du bro's cleves.
the best replacement would be the ball end types.