i've only ran my 391's on stage once, for a matrix. it came out well, a little SBD heavy for me. but good none the less. I ran them XY @115, and from my experience XY kinda rolls off the bass a bit. I've always had good luck with DIN. '
for a room like that, depending on the crowd, i taped in an auditorium that sounded really live and open, and i taped from the balcony, I liked it, since i liked the sound of the room. On stage would have given me a more upfront sound obviosly but onstage you don't get the sound of the room. Personaly i like that alot, so thats what i generally go for. good luck man, hope it comes out alright.