Personally, I wouldn't aim for the first show as it seemed the busiest and most chaotic. I've just checked my patter and there 2 shows that night, one 8pm-8.30pm and the second 9.30pm- 10pm. The show we saw was blue which only lasted 20mins so if I were doing it again I would head straight into the dome at 8.40pm, have my pick of the seats and get a drink brought to you as the waiters were circling anyway and just sit down and relax rather than stressing the queue for the first show.
I only know this as we headed back there at about 8.45 ish to speak to the Entertainment director about how the person in front of us in the queue was speaking to him & other staff earlier and I wanted to say that not everyone felt the way he did and no-one deserves to be abused by anyone like he was by the "man" (I can't call him a gentleman as he certainly wasn't 😤)