grahamp
Subscriber
I was doing some research on 2x3 film backs, and found this page, which I do not recall seeing mentioned before. It is a reasonable survey of Graflok 23 (and some 45) backs and camera compatibility from Mercury Cameras . I cannot attest to the accuracy or completeness, but it does seem to cover most of the commercial offerings in the 2x3/6x9 scene. Take up any errata with the company 
The Downloads link has some interesting lens scales for lenses used with their stereo camera which might be useful for those needing to re-scale a shutter or aperture.
I have no affiliation with the company - but I have bought from them.

The Downloads link has some interesting lens scales for lenses used with their stereo camera which might be useful for those needing to re-scale a shutter or aperture.
I have no affiliation with the company - but I have bought from them.