A photo of the cast from a beloved television show.
Explanation:
If we are talking about engaging the audience's emotions, we need to touch their hearts with something they are familiar with. A photo from a beloved tv show will probably trigger some positive feelings and emotions because they might remember the characters and they might feel nostalgia. The speech will catch everybody's attention if a photo from a beloved cast is used.
In this scenario, yes, you should wait. If you know that there is a possibility that you won't even show up and that there will be extra seats anyways, there's absolutely no reason you should rush to buy the tickets and risk wasting money.