How wide a saddle do you need? And do you do better with T-shaped, or more pear-shaped? Start with the major fit criteria so you can eliminate a whole lot of saddles that won't work for you, then move on to the more subtle differences.
Harder than tensioned leather pretty much puts you on one of the uncovered carbon saddles. Expensive... and I think all of them are rather narrow, although again you don't say how wide a saddle you need.