Hey bud, I am actually a student studying towards my doctor of pharmacy and yes, I too I am working on controlling my stutter. I truly wish propranolol was the answer but it isn't. From my knowledge it is indicated for reducing your blood pressure through vasodilation(making your blood vessels wider). Sure there might be tiny relief of anxiety that comes with it but if it were the answer to all our problems, everyone in this subreddit would be on it. I'd say my stutter is 90% controlled and the answer is constant speech therapy. I know its not what you want to hear just a day away from your presentation, but when you are up there just remember we are all up there with you. it ain't much, but take care eh