John, I'm going to tell you no more than you already know.
Because of the varied levels of turning ability in any club you can't please everybody. Personally my pet hate is an instructor who says, this is what I'm going to turn - and does so!
It's not what you turn, it's the interaction with the audience, and they can sometimes be hard to get going but if you can, you've won. If they don't ask questions, you've got to ask questions force the two-way banter, find the one or two members who interact and build on it. Stories and Anecdotes help but don't make them too long or too rambling.
As for the turning, yes turn what your currently practised at, bowl, hollowform, spindle something, or techniques for finishing or colouring. What we want to see techniques and explanations, hear about the tricks you've learnt, why you do some of the things you do. We want to learn from the demonstrator not feel like we're at a show where everything is choreographed and we have no say in the production.
Regards,
Bryan