I think I did it! I have obtained a much smoother action with the 12.5" ballscope. After a few emails were exchanged with a fellow ballscope maker in California, I discovered the magic formula for the right amount of static friction.
You may recall that the scope had way too much static friction (stiction as some call it). When you start to slew the scope, it would lurch from the effort of getting it going. Originally, I was using 24 1" square teflon pads at a 45 degree angle. I then cut it in half at 12. It was not improved. If anything, it got worse.
Jay (the ballscope maker in California) suggested cutting a notch around the inside ring where the ball would rest. Then use some PTFE tubing to sit in the notch. The weight of the ball would hold the tubing in the notch. So I built a new mount following his suggestions and ordered some of the tubing from McMaster-Carr.
The scope works like a dream! Nice smooth action with minimal stiction.
I will post some pictures soon.