It can also vary seasonally and is different from a first show of the evening to a second show. When there are 2 shows, minimum one hour for the first show and 30 minutes for the second show may be good enough. You can judge based on where the line is for the second show or ask a CM. When there is one show, and it's busy, you may need to be there 90 minutes before. First week of August is usually still "summer busy."