No one really knows for sure till you trip a breaker. Those outlets are intended to run a boom box or floor scrubber, not to put on any real production. Also I would think real hard about scaling back on how much sound you pump into that room. It really is one of the worst rooms I have mixed in.
Agreed on all counts. The acoustics are a huge mess. Less is more in that room. Anything you can do to treat the acoustics will do much more than more power to the speakers. If you had a choice of getting a budget to rent amps, or getting a budget to rent a curtain to hang to absorb the sound, I'd go the curtain route in a heartbeat. Not only will it sound better, but it will make the room look nicer as well.
I have mentioned that concept to the organizers in years past, so if you hit them with the idea, it won't be the first time they have heard it.
Your event does not need ear bleed levels. Intelligibility is the weakness. Anything over 105dB is too much for that event. 2 SRX722's would be much better than 4, as you can get much better pattern control and keep the sound off of the walls. 4 in that room will make a mess.
The outlets in the room are not labeled, so getting circuits is going to be a crap shoot. I don't believe there are any high power taps in that room, but they may have added some at some point. Some places can be ultra sticklers that makes it nearly impossible to install temporary power. When I've done work at that school in the theater, they were pretty lax about letting me get the work done without much fuss. Hopefully they would be just as accommodating in the rest of the building.
