I would guess the concert will be a little over 3 hours. I don't suppose it would be too much to ask for someone who has actually BEEN to a concert this fall to answer the question.
Wow, I just love this forum.
Since the poster's not Rob, we couldn't answer

honestly, i don't remember how long it was, maybe 3.5-4 hours so if it starts 7:30 it'd probably get out at 11.
the reason others didn't respond is because we can't dissuade you from going, so GO and you'll have a great time.