I would think that unless like everyone with a LL showed up at once you wouldn't have to wait too long with a LL. As long as it is the same setup, the LL lane going to its own Mickey meeting room. We did have to book our return time pretty far out in advance, it was fine for us because we booked it during our mid-day break for a return time after dinner at 'Ohana. I think it was worth it though, they also weren't rushing in the room at all and you could take your time and get whatever combinations of photos you wanted.