John, you've got the right idea in wanting to get the internal sub crossover out of the way, but since the SVS has a switch to completely disable and bypass its crossover, it's even better to use that instead of turning the control all the way up.
On the topic of the thread, when I'm playing two channel material on one of my setups that has a sub, I certainly use it, since it's just as helpful as with multi-channel material. I always set the mains "small" regardless of how good their bass is, to let the sub handle what it can do best while taking some of the lowest bass load off the mains.
