You want the epinephrine and norepinephrine, a beta-blocker would take that away, and while it might decrease anxiety could keep you from being as sharp as possible. You can still be sharp on benzos, just as long as your not taking a huge dose.
I'm really glad propranolol was the first suggestion. It can be quite effective, I was prescribed for a job making announcements to hundreds of people at a time and it made things a lot easier. Gabapentin is a good bet as well.
I'd stay away from benzos for this purpose, personally.
^ the main problem with taking an upper and a downer is that one can mask the other, making it easy to take too much and to overdose when one wears off. There is no inherent danger apart from this. Doesn't mean I think it is a good idea for a speech necessarily though!
Propranolol can work really well and less chance of you forgetting your words because you are benzo'd or talking-far-too-fast because you are stimmed imo..
Pretty much. I have had psychiatrists say taking the two together can be safe, if used appropriately. They aren't polar opposites, they work on different parts of the brain.
Nevertheless I'd recommend setting a limit - say 72 mg Concerta and 1 mg Xanax combo and not really exceeding it during the course of the effects in order to avoid potentially dangerous situations.
^ sounds sensible to me - always a good idea to keep doses as low as possible, especially if you have something important to do - personally I'd still tend to stay away from benzos or stims but in low doses that you have taken before (and taken combined) before it shouldn't be too much of a problem.
As the OP has given their public speech by now so I am going to close this, but if anyone would like to add anything feel free to shoot me a pm!