STS....don't just buy a clamp.......this IS THE opportunity! Show up at the LBS with saddle and post in hand and ask for a "good clamp" If the shop is any good, they'll tell you they don't make "good" clamps any more, you have to salvage them off old bikes. Maybe they'll dig into their parts box and find you an old Ideale or BSA clamp.

From that day forward, they'll know that you know they have the good stuff in the back