The altitude bearings were incredibly smooth and silky, in fact too much so. It required perfect balance in order to keep the scope in a desired position. I roughed up the PVC with a Dremel tool to provide more friction and that helped make the balance a little less critical.
A second issue was holding the altitude position when changing eyepieces or when an enthusiastic youngster bumps the eyepiece. I solved this one with a small clamp and a small angle bracket positioned very close to the PVC bearing. Simply position the scope, and clamp the bearing to the angle bracket. You can now change eyepieces or even give the tube a good rap and it remains on target.
A fishing leader keeps the clamp near at hand, and I usually store it when not in use by clamping to to the top of the bearing.