You'll probably get better power usage out of the 8"'s by using a low shelf to roll off your arrangers low end, or at least turning off any <90Hz boost you might have on, and muti-band compression low end boost.

There really isn't any point boosting frequencies that the speaker is inefficient at reproducing. You use up ALL your power amp headroom trying to push speakers into doing something they can't. Fran has the right idea... you want to get dance levels (even moderate dance levels), bring a small sub and suck those frequencies out of the 8"'s... That ought to clear up the thermal overloads.

For monitoring use, I'd brickwall 150Hz downwards. No point in lows in monitors, anyway (just makes the stage muddy).

As I've said before... my 824's go flat down to a very solid 45Hz, and go lower with some rolloff, but there isn't any way in HELL I would take them out and try to use them on a gig..

They are not built to do that, any more than those 802's are built to have robust bottom at dance floor levels... At quieter levels and smaller venues (like my 824's) they can stay nice and flat all you want, but be realistic... ANY gear, from the humble 802 to a Vertec system has a point beyond which it can't reliably go. Recognizing that point before you do any damage is the hard part!