Let me say that I am a distributor of Tufo Tires so I am prejudiced. Here's a few things to keep in mind on the subject of tubulars;
1. Using the tubular tape with non-Tufo tires is dangerous. Not because we want you to buy Tufo tires; well, really we do, but the tape is specifically designed for the tape on Tufo tires. The tape is 100% cotton and very absorbent. Those who know tubulars see tape covered with latex and other materials. In very hot and cold weather the extreme tape is best but otherwise, the regular tape will do.
2. The roundness of the sidewalls of tubulars means that a 21mm tubular is close to a 23mm clincher which must have a more abrupt drop off for the tire bead to work. Also, most tire manufacturers are not very exact in their measurement of width and weight. An example is a Victoria Pave, a really nice tire, is advertised as a 25mm tires but is narrower than a Tufo Elite that is advertised as a 23mm tire. Tire weight is almost always understated and sometimes by a big margin but the Tufo S3 Lites' weight is guaranteed. Usually they are under the advertised weight.
3. All of us recognize that the old silk tires or Egyptian cotton tires with latex tubes have the best feel of any tire. Dugast comes as close as you are going to get today and they are great tires but expensive. The downside of the latex tubes was that you had to pump them up every day and during long track events, I used to pump them up between races. Tufos are tubeless and leak about 5psi a week. I pump my up once every couple of weeks if I remember. Finally, ride feel comes from the suppleness of the tires. The higher the thread count, the more supple the tire. But a higher thread count also means that the sidewall is thinner. It is difficult to judge Tufo's suppleness by feel because of the lack of a tube but only Victoria has a higher thread count on it's top end tires.
4. The leak sealant can be put in before riding or it can be put in after getting a flat. You do not need to remove the valve core if you are out on the road. There is an internal thread in the top of the sealant's tube and it threads right on to the valve. But if you have extenders then you are stuck. Tufo also has some syringe like tools to insert the sealant.
5. While I've urged Tufo to make a classic type tire in at least 25mm width, I haven't been successful. But we do have a 28mm tire called the Diamond D. The catalogue only shows them with red sidewalls but we have them with beige sidewalls and they're pretty cool tires. They are sort of a slick cyclocross tire and durable; however, since they are meant for cross, the compound used in the tread is pretty soft and you won't get thousands of miles on these tires. But they are sticky and good in rain and snow. I'm sure Dale can get these tires for anyone who is interested.