Before giving up on the scope's altitude bearings, try locating a sheet of pebbly, gloss formica. In the past, Wilsonart Ebony Star Formica was the go to choice, but I think it's discontinued, so you'll have to locate something similar. Ask around on the ATM forums what's best these days. Cut the sheet into strips and glue them to the curved bearing surfaces attached to the mirror box. Next, locate some blocks of Teflon (PTFE) and countersink screw them to the rocker box, one toward the front and one toward the back of the bearing surface. Check that Obsession's bearings, I think you'll find a setup similar to this to guide you. Nylon can be substituted for Teflon if the motion has too little sticktion for your liking.