This is like deja vu. About 6 weeks ago I received a phonecall from someone asking me the very same question. He came to me for 3 sessions before being best man at his brothers wedding. He actually phoned the following week to tell me how well the day had gone and how much he enjoyed the wedding.
I’m not so sure about the best man being responsible for setting the tone. Not everyone is a comedian or a polished after dinner speaker. From my own experience I would say, don’t try to be something that you are not. Work with the skills you have, keep it simple and short if you want and leave the long speaches and jokes to the others.
Hypnosis can certainly help calm the nerves and help you participate and add to your friends big day. Call me to arrange an intro chat if you want to learn more about hypnosis and hypnotherapy.