I used some HEAVY, but strong LX hubs with DT Alpine III triple butted spokes and Sun CR18 rimmed wheels last year. I was new to 'cross, and figured I needed super strength...wrong. I saw super light road stuff getting whacked around and coming back for more. Well made wheels are strong enough to take a wooping. Your Ultegra/CXP set should be nice. I'm planning to run 32 hole Ultegra/Open pro...because I already have them. I have a set of Ksyrium SSLs for road racing, and may give these a go on some of the smoother courses here in New England. Its not like I'm sponsored and can get wheels when I trash them.