Zaehnsdorf’s A Short History of Bookbinding, originally produced as promotional material, contains some nice images of his premises and details of several steps in binding. Even in these low-res google scans, interesting details can be observed: the headbander using an upside-down plough, the massive finishing press with wood top (replaceable, to protect the press from glue?) used for spine lining and finishing, the sewer working inside the frame, etc….
Notably, some of the steps are described as a generic action — “backing” — while some have the specific names for positions — “collater, cutter-out and coverer”. Small clues like this can help to understand the divisions of labor in Zaehnsdorf’s large nineteenth century bindery.
I also noticed that Zaehnsdorf’s The Art of Bookbinding is available as a 6 hour audio book. It would be an interesting experiment to listen to his instruction, while following along. I doubt I will do this, but if you do, let me know how it works!