I find they're nicer when you give them the passport in such a way that they first see your O-1 visa. Covertly letting them know that you're an "exceptional ability alien" right off the bat, sets the relationship off to a good start.

The time when I said "Oh just coming back from vacation" before the lady saw my visa ... well, she was much less nice about it.

Ah, I don't have a visa, I only travel to the US to visit friends, more or less.

The queue will depend on the airport and the number of border agents on duty.

A difference between 24 minutes and 1 hour is only slightly more than 2x, so it's not extremely significant in the grand scheme of things. Security lines on domestic flights can last longer than 24 minutes.