We attended the 8:15 show on Saturday, Thanksgiving weekend. Got in line about 7:40 and were seated in the first row, center right, immediately behind reserved seating.
Several hundred people who got in line after we did were also seated. As always, approximately half the theater was held for standby. Disney does not sell out the theater to packages, nor do they attempt to. As of this writing anyway, seating is approximately 50/50 for packages and standby.
And we spoke with a family in line that had gotten in to the first show by queuing for about an hour. I suspect that with this event, as other concert series in this theater, the 3rd show is the most lightly attended.