[knomadd]

It sounds like you two are talking about different points. I may be missing it, but it sounds like Brian is talking about the joint between the mirror and the arm, not the ball joint on the mirror or the roof mount joint. There is simply a screw that slides through one side of the "arm" and through the mirror connector (how the ball joint is held to the arm), then tightens on the threaded side of the arm. I don't think you can do much to get this connection tighter. You may try adding a shim to make the gap between the arm and mirror connection tighter. Just a thought.

If I understand your question correctly, and this is really what you're asking about, I too am curious how you'd fix this, so let us know how you fix it.