I've tried klonopin twice I think for presentations. One time I started to sweat like crazy when up there and my stutter was worse. The second no sweat, but stutter was bad too. On the other hand I've also had some presentations around the same time that I didn't take anything and things went smoothly. Another one that I took that helped a bit was propranolol, this one is used by a lot of people in general for presentations/performances from what I gathered.