Hi Keith,
We currently have a 12"/F5 binocular telescope that was built by Mark Suchting as part of our 3RF OZsky Equipment. It works very well. We also have a 22"/F5 binoscope that was built in the USA and it doesn't work so well due to stability issues. It will eventually be re built by Peter Read at SDM Telescopes. In the images below you can see the white 12" binoscope towards the rear of the observing field and in the image of the 22" binoscope you can see how flimsy the truss poles are. The flimsy truss poles cause it to wobble unnecessarily which makes it extremely difficult to keep the images merged.
I suggest you contact
Mark Suchting or
Clive Milne who have both built successful binocular telescopes in small and large apertures, including a 20"/F5 binoscope, which does work. I have given you an embedded link to both of their IIS profiles. You could also contact
Dave Moorhouse in New Zealand who has also built several successful binocular telescopes.
Cheers,
John B