Sorry Grant. Just saw this thread.Grant Bunter wrote:Thanks Brent.
Any other takers?
My two bobs worth.

I use REW for EQing in my home theatre. It's a free windows program (google "home theater shack") or go to http://www.hometheatershack.com/roomeq/. When I eventually build my BFM stage system, I will try to use REW and my laptop for venue EQing. I'm not familar yet with the full capabilities of the DCX, so maybe a program like REW is not needed.

When EQing, reduce the peaks but try not to boosts the dips - you will use up all your amps headroom. Just work on the peaks.
Using a Linkwitz-Riley crossover, your sub and top should stay in phase. However, that would only be with direct firing drivers. Horns have a delay which you would have to compensate for. Also if your top was, say a DR250, it's internal crossover may also affect it's phase.
I personally believe stage subs should have a minimum 48dB/oct high pass filter around 35 - 40Hz.