Here is the C80ED and camera assembly ready for imaging. The fan is running, so the DSI is cooling (gives around 15C lower than ambient).
This is an older picture, using (1) direct mounting of the Crayford to the OTA using those three holes,
and (2) a long 4" Televue extension tube, with the focuser racked in.

Flexure is a huge problem here, showing up for 15 minute+ subframes. The mounting rings are far forward on the telescope assembly,
because (a) the stock focuser was very long and therefore the OTA was short, and (b) the Robofocus does not allow a mounting ring around the focuser body.
The OTA is held pretty well, but pushing the rear ring farther back would certainly improve flexure.

Changes since this photo was taken: (1) Adapter Ring is now being used, allowing for a much more solid mount of the focuser to the OTA,
(2) 4" extension tube has been replaced by a 2" Televue extension tube, allowing for the draw tube / extension tube interface
(a big source of play because of the single screw) to be moved rearward, (3) shims around the draw tube / extension tube interface,
and (4) a third Losmandy ring assembly at the rear of the dovetail plate, to support the extension tube.