Unless things have changed within the past few months, there are always two WoC shows a night. If the crowd warrants - usually determined by the speed at which the fastpasses sell out, they will add a third show.
However, because of the nature of the show and where it is located, the back section of the lagoon (TSM, CS, MSW, etc) is closed when first show starts.
Since the whole park is open before the first show, there is no waiting area needed for the first show audience. For the second (and third if scheduled) the waiting area for the audience is located behind GRR - which is the queue line for the WoC fast passes.