I had thought about that but didn't want to since I'd lose LFE channel to the subs. I'm talking about how the SVS subs have their own EQ adjustments on the amp plate.
There's not enough "stereo" in bass to tempt me at all to setup on high level connections like that, but I don't have the subs positioned where that would do any good and use four subs anyways. It isn't necessarily a bad thing to get your subs setup with the SVS dsp before running Audyssey, tho I'd not do the LFE+Main thing (I recently revisited it too, prefer just the LFE setting with a cross at 100).