Studying these geometries is just a part of the research I will do. I will be looking at other frame designs. I just have easy access to these so they were first. And since they are vintage, I thought I would post here.
That said, there is a long tradition of converting "race" bikes to a utilitarian role. Italian manufacturers took advatage of this from the 50s through the 70s with their Sport models. A definate cross between the bici da corsa and the bici da citta. No reason to believe a "racing" geometry couldn't be used.
Also, for the competition, I am looking specifically at a commuting bike, not an all out workhorse. I have gotten 100 responses from the first survey I done and there is a definate need for a commuter to double as a fun bike for other than going back and forth to work. If I would have one suggestion for the competition, I think there should be different categories of a utilitarian bike. Something for car-free-living is apples to oranges compared to what I use as a commuter.
This is indeed food for thought.
Different folks often ride very different bikes in the same event. Think about PBP, just as an example. I am sure there are lots of modern (even fender-less CF) 700c race bikes used for that ride, but some people ride full-on randonneuring bikes, and everything in-between, I suppose.
When Jan Heine set the mixed-tandem record in PBP with Jaye Hayworth, they were on something like a 1952 Herse tandem. Certainly an outlier of the (tandem) bikes in that event!
Personally, I am becoming more and more convinced that non-oversized steel 700c frames with the 'sport bike" geometry of the 1970s can do an awful lot. Think circa 73-degree HT angles, moderate (50-60 mm) fork rakes, moderate chainstay lengths, moderate BB drop, lots of tire/fender clearance, etc. A geometry like that can do a whole bunch of things quite well, I believe, and you can fine-tune the geometry variables as well as the tubing variables depending on intended 'primary' useage....