As far as I can tell, there are about as many ways to glue on a tubular tire as there are people who do it. For a new tire on a previously glued rim that works out to about 4 coats, 3 on the tire and one on the rim, over at least 3 days, for me. One tube did the job. I only have one set of tubular rims, so I don't do it very often, so one tube at a time is enough for me. This stuff always works, even for an amateur.
Product goes on easily, dries clear, and sticks very well. What I like best about the Conti cement is that is does not squeeze out between the tire and rim once inflated. I am a former Cat 3 racer now over the hill.
All sewup glue is messy, Continental glue is clear and doesn't stand out as much. I had to remove 20 year old glue from a rim and it come off easily with citrus solvent. It holds the tire on the rim and that is all I ask of it.
I applied per Continentals recommendations for this carbon fiber application. The cement dries too quickly to allow for final alignment of the tire to side and particulary around perimeter. It ended up to be loose at stem end, while stretched at other for tire to be out-of-round. The new tubular failed at stem 30 miles into a road race... !!! I may try applying two coats, or to use cement intended for aluminum rims as another friend of mine did, I believe successfully. I would appreciate any suggestions. I have applied over one hundred sew-ups a few years ago without any problems for team members.
Continental Cement is my standard of choice for training and racing tires. Compared to other major brands it lays down very nicely. Other brands tend to be too thick and harder to manage. One tube is sufficient for two tires. I use it on my carbon rims without worry. Instead of a single base layer on the carbon rim, I use two thin layers. Continental cement has never failed me in over 20 years of riding and racing.