It’ll be fairly peak most times … as peoples routines are dictated by loads of different bands . But I’d imagine quieter times will be evenings and especially during headliners . That said there’s 50 cash registers so things move pretty fast
Whenever I've used it - around lunchtime-ish - the queue has been out of the door but moves very quickly. I think they stagger entry but there seemed to be a good amount of tills so people moved through quickly.
What are the times to avoid it?
When I tried to use it a couple of times last year the queue was going out of the door (12.30pm ish on the Saturday was one iirc.)