2009 - confirmed with Spirit of Aloha CM that seating assignments within each category are done before you get there.... and based on the number in your party and when you made your ADR. The earlier you make your reservation before the day of your ADR, the better your seating. Seemed to be true, we booked category 1 right on the first day we could (was 90 days then, now 180) and we were right up front.
Enjoy the show and be sure to stay for the fire dancer.