The windows were smaller than you think -- one parcan per window was enough (I believe they were actually 1.2K "firestarter" VSNP globes actually.)
Being on a low stand and bouncing up into a mirror on the ceiling and back down through the windows was enough spread to fill the window.
The bounce back from the backlight onto her face wasn't from a mirror, but a white card, whatever was small enough to hide behind the locker door (I think it was 2'x3'). For the close-ups, I swapped it to a 4'x4' card.




