Slightly different reasoning:
If you don't want to tweak the night away, run the mains in "limited" (I assume this means 100hz x-over) and insert an automatic room EQ (like the SVS/Audyssey box) between the pre/pro and the subs. By crossing at 100hz, the Audyssey will room correct up to that frequency - which is where your room causes the most trouble anyway. It will also set level automatically. There will be no additional circuitry between your pre and your main speakers above 100hz, where you might actually hear it.
Caveat: I use the Velodyne SMS-1 for this task (it's more flexible than the SVS and sounds great), but it requires a lot of tweaking for best results. I haven't heard the SVS/Audyssey unit which performs the same EQ automatically. However, KR, who reviews at Stereophile and ocassionally posts here, has compared the Velo with the Audyssey and prefers the latter, hence my recommendation of the SVS/Audyssey. Since you evidently have the x-over in your pre/pro, you don't need the Velo's internal crossover, which would be another reason to opt for it over the SVS.