The 13 inch Coulter I bought used moved very sluggishly so the first thing I did was replace the azimuth bearings with textured Formica and Teflon. The next was put a JSL Crayford 2" focuser on it. I added a Telrad. I epoxied a strip of Velcro to the top of the tube at the base so I could move a 3 lb. lead shot bean bag counter weight which my wife sewed up and down it when using different weight eyepieces. I was going to replace the 3 1/4" secondary with a 2 7/8" but never did. I even had plans to retube it with 15" pvc but didn't get around to that either. I used some hole saws on the the base to lighten it. I stopped after taking 5 lbs off because it was beginning to get slightly top heavy. Deloy Pierce