I'm personally a fan of setting it to auto-host, so it hosts a new turn as soon as everyone's turns are in. If someone goes more than 24 hours, then we just get on their case on the forums, and if that doesn't get them in you set them to AI.
That way we can make as much progress as possible, while still being pretty flexible. And I always found that when someone misses a turn, they get out of the loop pretty fast and find it hard to get back in the game, thus AI.
Also: I'm down to act as a mentor as well as hosting. I think I posted that earlier, but I don't see it in the OP.