I've never been a fan of non-round case chronographs, like the Royal Eagle, because the outer chapter shows less precision than the watch can produce. It just looks silly to me. I think the height of beauty was the round case, teardrop lug chronos from the 1940's. Some of these appear in two tone cases, which seems like it would be difficult to marry gold with steel to create a strong case.
Back in the 1930's Vacheron had a cushion shaped chronograph with one or two buttons, and a round dial. I think the outer chapter was marked as either tachymeter, or pulsations. Does anyone have any more information on this watch? Movement, dial, case size?
I've seen illustrations before, but never any actual photos of this watch. Can't find any info on the caliber or reference. I wonder if Doc already has an example in his collection?