But I don't worry for that: I'll put a shim, in front of the groundglass, exactly of the same thickness of the difference.Regarding the focusing difference between your focusing back and Cirkut Attachment, I wonder if the camera body (or at least the focusing back) aren't original to the Cirkut Attachment?
Exact ! I counted the teeth: 290. Then measured the outer diameter: 232mm, that is 9.1338 inches. 290/9.1338 is 32 (rounded value) ! So, it's a "diametral pitch". See this drawing (original in http://www.engineersedge.com/gears/gear_tooth_parts.htm :I believe gear pitch is a term indicating somewhat the number of gear teeth per length of measure.
And here the formulas for spur gears:
But, it would have been better, in the Cirkut formula, to use plainly the number of teeth, avoiding a "rounded value" .... After all, to explain the movements in a Cirkut camera and its relative "speed", it's all a question of ratios among teeth in different drives. Isn't it ?
A panoramic photo of Venice - Piazza San Marco, would not be so bad... Well, probably too many people going around. Some nice "blurring", however...