How long are the performances?

Every tour is different. The headliner chooses everyone's set time before it starts.

a whole set is usually 6 or 7 to 11 or so depending on how many bands are playing.

Depends how many acts are on the bill. Openers typically get 30 minutes. Headlining acts typically play anywhere from an hour to an hour and a half. Most shows at this venue are done by midnight, unless they're late shows