Geoff, The hubs are just hollowed out to go over the original ones (they are 8" diameter) and they work well and are attched with some knock down bolts through the original holes in the plastic hubs. These are my prototypes and I am working on some that are attached to the classic box so I can balance the tube better and without the top half so they don't look so darn big. Yes, I had to chop into the base, that was the point of no return
Ian, No the Telrad has never given me any problems. The only balance problems I get are when I am at zenith or using a large eyepiece near the horizon or when I have the solar filter on. Using magnets fixes all those problems but to be safe I remove the Telrad and finder scope when observing the sun.
Cheers