why only UST?
why are you limiting your self to only UST specific tires? UST is just a standard (I think originally by mavic), but there are tons of tires that work fine tubless but are not UST certified. UST tires actually tend to be heavy because they have thicker sidewalls than most other tires, tubless reccommended or not. I run tubless and have never used a UST tire. I do use tires that are intended to be run tubless (Specialized, Schwalb, etc.)