Headmaster Bontecou actually arrived for something early (he'd given himself a two hour head start) and he spent that early time setting up. First, he banished the tables to the sides of the hall and then he moved the benches so that they were all facing the raised dias. Then, he banished the staff table to the wall and set out some of the staff chairs along the side, leaving the middle open for the cage and podium. He figured the younger students would go in front with the older (and presumably taller) students in the rear with any other staff that wouldn't be directly involved with the assembly.
Once he was ready, he waited for the staff and students who were coming. They still had some time...
ooc: The layout (generally speaking)
dias with cage, staff chairs, & podium
{ }
\\________P_______//
----bench for 1st yrs---- ----bench for 2nd yrs----
----bench for 3rd yrs---- ----bench for 4th yrs----
----bench for 5th yrs---- ----bench for 6th yrs----
----bench for 7th, tall peeps, staff----