Shows are on twice to cater for the two sittings, most nights they are on about 7pm for the late dining guests, i.e. pre-dinner, but on a couple of occasions they were on after dinner. There are two ice shows and each was performed on 4 occasions, times are publicised in advance and you pick up tickets for the show of your choice. If you make the effort to go when the ticket distribution starts you shouldn't have any trouble getting tickets for the show of your choice. Timings of ice shows didn't clash with anything critical, e.g. one was on a sea day at 2 and 4pm and another was on at 7 and 9pm on a night with no other main show.
No all shows are timed so that both dinner sittings don't miss out. (2 shows a night).
As before with the two previous answers there is nothing to worry about as there are 2 shows a night. Have Fun!!!