PSA - don't rely on the INVERT DIRECTION setting in mechanical parts, it sometimes doesn't work.
I figured out the issue is parts added with symmetry don't work when inverted, it's a known bug that apparently is not fixed by 'KSP community fixes' mod.
I wanted it inverted such that the KAL inputs would be identical and the tracks could be copied, unfortunately the solution is: 'do not use invert' - and make the KAL tracks and movement limits appropriately.
At the end you can see why it's important I use 2 servos, it doubles the available torque to increase control authority, but more importantly it adds reinforcement, confining the pod movement to one axis, where before it was flopping about as if connected by a ball joint, not a pivot.