Perhaps someone has mentioned this already... There is a terrific new product that repairs tubular tires -- Vittoria/Geax Pit Stop. When you get a puncture, you remove the offending material (i.e., glass, thorn, etc.), attach the can of Pit Stop (which contains compressed gas and latex foam), and fill up your tire. That's it! It takes maybe about 3 to 5 minutes to repair your tire. [Tip: make sure that you have a good seal between the Pit Stop nozzle and your tire valve. When you put downward pressure on the top the nozzle, the latex foam is released.]
I've used it on a 1980s Clement Criterium Seta. It works great! A friend of mine successfully used it on a modern Vittoria CX tubular.
There are two versions of Pit Stop: (i) Vittoria Pit Stop Road, and (ii) Geax Pit Stop Magnum (for mountain bikes). As far as I can tell, the Pit Stop Magnum has more air and more latex, and costs the same (about $10) as the Road. So, I recommend getting the Geax Pit Stop Magnum (rather than the Pit Stop Road).
Nowdays, I carry a can (which weighs about 80g) along with me when I ride (in addition to the spare tire, in case of a blowout). I only wish that they had made this stuff 36 years ago when I started to ride tubulars.
You can get more information at: http://www.geax.com (look under "Accessories").
Happy riding!
Jim Kadonaga
Del Mar, CA