I bought a GSO 12" back in 2003 before they added the Crayford focuser and the fan. I wrote up an article about it for the CAS "Southern Cross", but as the subject of GSO 12's comes up from time to time, I though it might be useful to make it available in PDF form in case anyone was interested.
In particular it describes how I modified the azimuth mount to improve it over the old vinyl clad chip board it used to come with. My first experiment was to sadwich the roller bearing between two laminex disks, then I replaced the bearing with a conventional Ebony Star and Teflon bearing.
In December 2003 I sent a copy of the article to Lee Andrews, who sent it to Jim Sheng, and I was quite amused to see subsequent GSO scopes come with two steel disks sandwiching the roller bearing. No royalties paid, alas
The Ebony Star and Teflon bearing is a better (smoother) bearing than the steel disks and roller bearing that current GSO (and Lightbridge) scopes come with.
And the fan is definitely a very important addition if you have one of the older pre-fan scopes - you can mount a DSE PC fan on the GSO mirror cell with strong rubber bands and it works well.
The PDF? For the moment it's at
http://www.dcnicholls.com/misc/gso300.pdf
DN
Canberra