Yes, apparently the focus is changed by moving the secondary - nice and simple and no mirror flop
My RCOS moves the secondary mirror to achieve fine focus - nothing new under the sun.
Apparently all that stuff works OK. The lacquer seems to have have worn through in places on mine and as I understand it, its bad form to "polish" the old lacquer off, true?
Still any new stand I get made will not match the patina of the tube - probably not a real problem