You will know what you want better than I do, but here are some thoughts. Your toastmaster / master of ceremonies must be capable of doing the job you expect and should give the results you want. There are many of us out there to choose from and we come in a range of styles.
Some toastmasters have lots of impressive qualifications (usually on display) and are rigorous about ensuring formality and protocol. At one extreme, this procedural behaviour could clash with the informality you want and, in some eyes, toastmasters might seem ‘officious’ and ‘pompous’.
At the other end of the scale, a toastmaster could be over-casual and behave too much like a guest at a party.
These are two extremes, of course, and those of us wearing the red tailcoat will have our respective comfort zones within that spectrum. Even so, a good toastmaster will be able to adapt to give the right balance of formality and relaxed behaviour for your event.
I believe that I’m adaptable and sit somewhere around the middle of this scale. Phrases that brides have used about my style are: ‘keeps control in a relaxed and humorous way’, ‘solves problems if they occur without disturbing us’, ‘close attention to detail’, ‘helps to give every one of us an enjoyable and memorable day’.
Whatever you decide about your special day, I hope you get exactly what you have dreamed for it; if I can help or advise in any way, please get in touch. Thank you.