Hi :) .
Same for me, it took 24 auditions to unlock the slots.
Given the length of these auditions, I did one a day, continuing my daily routine. I just replaced my long night assignment with these auditions.
And yes level 80 and a rehearsal room for the first mission of the table, the second is at level 85 and the third at level 100, it starts to get long between each level.
Courageous :) .