It should be called Stage Entertainment
Many hypnotists new to the craft (and a few established ones) think that the hypnosis portion of the show is the most important element. While it certainly is the majority of the show, the induction is also an integral part of the show, as long as it's not boring to your audience any hypnotic induction will work. People love to watch just how the hypnotist puts the volunteers under. Now I've seen several hypnotists who take forty five minutes to an hour to get people under and that is a little too long . One such person does not even use an induction, he just tells the volunteers to "go along with it" and still takes twenty five minutes of faking it! My point being, do not focus too much on the induction and leave the rest of the show in the balance. When you lose sight of the fact that you are there to entertain, and if you do not have a well planned, fast paced show, you will find the audience getting bored.
Your induction is only a means to an end and not the show itself.
So how long is too long of an induction? I would try to keep it under twenty minutes tops. Of course the length of the induction depends on what kind of a show you are doing. You would need a longer induction for a corporate show and a shorter one for a high school.
So now you have them under, what to do next? You want to structure your show so it starts out with the easier things to do like stuck to the chair, can't remember the number seven and work up to the harder skits like watching a funny movie. Some hypnotists only do group skits and that's ok, but I like to interact with the people on stage on a one-to-one basis. Just keep your show well paced and lively. When working with a large group and you are taping the show for sale you want to try to work with everyone on stage so that you sell the most tapes.
Here is a little pet peeve of mine. I still see hypnotists making people bark like a dog. One of the first things people ask me before the show is will I make them bark like dogs or cluck like a chicken. My answer is always No. There are so many skits available to you which won't degrade or scare the volunteers on stage. Here are just a few things people are doing on stage. Telling them there are rats all over the floor; there is a scorpion on your arm and it bites and last, but not least, the room is on fire. These are examples (in my opinion) of negative suggestions that have a potential of doing more harm than good. One should always try to keep a positive attitude in ones shows and help to dispel the erroneous stigma attached to our craft.