I can add another data point to confirm that some builders did indeed use other than the usual butted 531/Columbus seat tubes, in larger frames, for increased stiffness. My 58c 71 Ron Cooper (racing) is this way, taking a 27.0 post, rather than the 27.2 that smaller Cooper frames took.
Additionally, I will volunteer my NOS Universal hoods of the old style as a moulding pattern, should Robbie decide to tool up for making repro Universal hoods. While less popular than Campy hoods, I do believe there is enough of a market for these out there, that the investment would be worthwhile. I also have the two different styles of NOS 'rings' and 'nipples', which go on the adjuster barrels of the Universal levers. For all those pre-69 Cinelli's and other Italian bikes, Universal are the only levers that will do. Despite thier lower leverage ratio.
Bill Roberts
Jacksonville, Oregon