Randy,
Thanks for posting.
It appears that the 350s have the type of response that you would expect from a traditional subwoofer (unlike the DSP subs). If your room was smaller, the 350s would be adequate but because you have such a big room, there is no low frequency room gain and hence with just the 350s on, your bass response suffers below 35Hz or so. That's where the 600 comes in to save the day with its flat response down to 20Hz.
Looking at all your graphs, I don't see a compelling need for the 350s. Put the money towards a pre/pro and/or an A1400-8. Your daisy-chaining problems would go away too.
