oh yeah, i forgot part of my comment, which was, "...but if you're going to be racing indoors, is durability going to be an issue?"
re: durability - when it comes to track racing, tires with unprotected sidewalls that are just the cotton, silk, or polyester (or whatever?) casing are definitely less durable than ones that are fully rubber. These tend to be race-day only tires, and that goes double if you're racing outdoors. (or, avoid 'em alltogether. at Nats in Rock Hill, I saw a lot of exposed sidewalls that had gotten shredded over the course of the week). Most gunwall clinchers that I've seen don't have just bare casing - they have colored rubber of some type or another.