Fascinating to see them stacked like that and to have the sometimes very subtle differences pointed out. What occurs to me when I see these vintage beauties shown together is which one was the best for diving. What I mean by that is that they were all designed for a specific purpose i.e. diving and all share the essential attributes that you mention but which one ticked all the boxes as "the tool watch" for divers? How important was the size of the crown? Did an alarm function feel safer than a rotatable bezel? Was the dial clearer on this or that one?