Thanks LouisN! It's completion was commemorated with a fine vintage!
The bike weighs in at 8.12kg with the Lyzene pump, empty seat bag and empty bottles. It's difficult to find comparative weights for a large bike. My Serotta Colorado II weighs 10.6kg. The seat tube length is 812 mm from BB to top of mast.
The wheels are HED Belgium C2 (Ardennes) laced radially in front, 2x NDS, 3x DS rear, with Sapim CX-rays 32 spoke to Shimano 7900 hubs. I built them from parts supplied by Jude at Sugar Wheelworks in Portland, Or. Weight of wheels with Schwalbe ZXs (way too fragile: 4 rides on clean roads, 4 blowouts, 3 ruined tires ), replaced with Michelin Krylion, is 1080 front, 1480 rear (with 11-28 cassette).
3T Arx stem, Team carbon bars. Shimano DI2 groupset.
I have no frame of reference for comparison of the ride quality with other carbon frames. Finding a large frame, especially here in France is a major challenge. I've had the Serotta since 1992 and it has served me well. Riding the chip seal roads around here was not pleasant however. My goal with the Cyfac was a bike which was at the same time stiff and comfortable. The Serotta handles descents with grace and speed, even on bumpy roads. I wanted no less from the Cyfac. It had to allow high speed descents with confidence. Finally, I find climbing the hills around here to be a chore. I wanted a bike which would help me in this area.
Having only ridden 3 times since it was built, about 100km so far, I would say that so far, it meets all of the goals. Chip seal roads are no longer an issue. I can feel the pavement, but it doesn't cause hand and butt ache. Climbing is now fun. Still takes work, but I feel stronger. I'm no spring chicken, but I'm not dead yet! Out of the saddle, it is very responsive, surging forward easily. I've only had it to 61km/hr on a descent, but it felt good an solid. The 7900 brakes have more stopping power than the 7403s on the Serotta (almost too much so as it is easy to lock the rear wheel). There is no discernible flex, but the bike is still very comfortable after 3 hrs of riding. I am able to run the tires at 100lb, vs 110 for the Serotta (same tires). I'm about 80kg. The HED rims are fantastic.
After having read various comments concerning steel vs carbon, I was concerned about a loss of road feel with carbon. It feels different, but there is no loss of sensitivity.
The process of selecting the Cyfac was rather long and involved. The options for a large, lightweight frame are certainly fewer than one of 54cm! I looked into and considered Parlee, Specialized, Cannondale, Look, Time, Pinarello, Moots, Canyon, Crumpton, Cervelo, several custom steel builders, Viner, and Colnago. I decided against each for various reasons. Maybe there are better frames, maybe lighter frames. At the end of the day, I am really pleased with the look of the Cyfac, the paint (partly my design, partly Cyfac std but a big selling point for me. I'm not interested in a stealth bike!), and not worrying about having it broken by the TSA or other shipping agent
So far, it's a keeper!