Hello One-eye Jim ~
That trials chainring was as I remember about 20 teeth 50% eggring.
The minor axis took it to equivalent of about 9 teeth and the major axis about 28. Tree-climbing stuff. The TA crank was specially modified with part of the inner ring mounts removed and mounting holes drilled, where they could ~ there was not much room!
It was all done by that estimable cycle transmission guru Chris Bell.
You may find some more information on http://www.highpath.net
Chris Bell teamed up with DWS when they both moved to Wales, but I don't think they are working togther as much these days.
I can't remember all the details of the gearings typically fitted to the production bikes. I do remember that the TAs were 28/44/&50something with the teeth milled off.
Rear clusters were really difficult to get because the hubs had french threading ~ it was this small difficulty that could be said to have caused the operation to close. Want to know the whole story?
I was knocking up prototypes using a variety of gearing combinations, but now I have what I wanted all along; The Shimano Inter8 fits the bill nicely combined with a couple of EggRings with digital shifting, donchano.