Thank you very much for it, I thoroughly enjoyed reading it. Regarding the movement: I rather assume that it is supplied by Dubois-Dépraz, and not modified by Bucherer. At least the unique big date layout suggests that origin.
I, too, think that the deployant clasp layout is not only unique, but due to the possible step-less adjustement of the strap also more versatile. However, when I tested the Evotec, I felt that the clasp is very uncomfortable as soon as the strap is not long enough, due to the large part protruding towards the inner side of the wrist. I assume that the strap is well dimensioned for you, so the clasp fits good without any modifications.
Regards,
Marcus