Photon Collector (Paul) has put a Bintel 12 inch on a GEM mount for astrophotography.
Here it is
As for the Optics, Pauls works very well, and visually looks great too. I once saw Jupiter through another mates 12 inch bintel dob and the detail at hight power was excellent, so yes their optics are fine. One little thing though, the original mirror coatings appear a little grimy, that is hard to remove. Paul has since had his recoated, it now sports a pristine quartz overcoated coating.
Scott