loose mirrors
Most of the wobbling is caused by loose housing and pedestals.
I don't know if you can get in to tighten the actual mirror. We tightened the screw inside the pedestal at the housing...that cured the worst of the jiggling, however I do still see a slight vibration at hwy speeds. Hubby thinks there may be a way to tighten the remote adjustment cable, but he's not sure. All our Corvette books are in storage. We may delve further into it after we get moved.
Perhaps you could try and bring this to Steve or Mikes's attention...they may have a better answer.
Silver