From my experience the best angle is often at the back of the whole crowd standing on some plateform so that you are about the same height as the stage and non of those hands holding the hopeless P&S can block you.
since most neighbourhood shopping centre don't have such big venue (20m is often enough) Just be sure that the lens have enough.
Of cource at places like Takashimaya civic plaza then it will be a different story, you need 600mm at least to play the whole strategy, astronomical telescope is better still.
If you are in the centre of the crowd then the hands in front of you will block.
Even if you manage to squeeze to the first row, the height of the stage will force you to have a high angle of elevation, then you get shots of the actress's chin and nose hole instead of her face.
since brother hazekang says that the venue is very flat (I assume it means the stage is not rised high), I will try to go there a little early.
See you all later!