The bike built up quickly, with no compatibility issues. Why would there be, when I'm just switching things over between two identical frames? I cleaned and polished the Campy10s carbon bits. I mounted the triple derailleurs with old-man knee-saving gearing. The new frame has short seat tube, 50cm but 53cm top tube, so now my seatpost is fully extended, not minimally so. I'm using a long stem and HS adapter to get the same riding position.
Ironically, if the 56x56 frame was a touch too big, I now have 50x53 that is a touch small, with compromises made to get it to fit me. The bike weight is almost exactly the same, 18.2lbs versus 18.5lbs using a bathroom scale.
On next episode of Guerc's tale of mental illness: Riding impressions.