I've been on Propranolol for nearly ten years now, on an as-needed basis whever the symptoms of anxiety are likely to be prevalent.
I take 40mg, or in particularly anxiety-inducing situations 80mg, about an hour before a stressful event. This effectively blocks a racing heart and is somewhat effective at controlling blushing (at 40mg symptoms are reduced, though not elimated - yet at 80mg I find no symptoms of blushing when I would otherwise go beetroot!). The sensation is quite peculiar, as I have become senstive to my body trying to release adrenaline and still get that cold feeling, yet without the subsequent shaking and blushing I became so accustomed to.
As beta blockers only control physical symptoms, you'll need to consider ways of dampening psychological anxiety. I supplement Propranolol with 10mg Diazepam or 2mg Xanax, which works like a dream for parties, presentations, and business meetings. I've got through a doctoral viva, numerous important talks and taught for two years while dosed up on a Propranolol - Benzo combination, and would have been a gibbering wreck without it. However this is not a strategy to use every day. Benzos have been a life saver for me, but they are addictive and zone you out, and I've even had memory loss on them - so be disciplined and use common sense in using them. Alternatives ways to deal with the psychological aspect such as positive self-talk might work. I've also learned other cheeky strategies - such as using handouts when presenting. Everyone's so focused on reading rather than listening and looking at me that the psychological anxiety drops off!
Disadvantages of Propranolol? I have asthma and sometimes get mildly wheezy on it. Even without asthma, your heart will refuse to beat hard so if you try to run you'll end up puffing on the side of the road while your cardio system asks what the devil you're up to pulling it in two different directions. I've also found that my mood lowers if I take Propranolol regularly - something to watch if you're naturally a bit 'Morrissey'.
Finally, it's easy to get prescribed beta blockers in the UK. I simply walked into the doctor's office in my normal 'natural' state and sat there shaking and blushing. After I stuttered that I needed help for social anxiety he simply took my pulse and wrote the prescription without further questions!
Anyway best of luck and feel free to ask any further questions.