Thank you all--really. I value this site for the experience and knowledge of the community but sometimes there's too much talking and not enough listening. However, each of you in this thread has been thoughtful, insightful, and very helpful. Rather than feel overwhelmed, I am left with the conviction that there are a number of viable paths and workable options--even for the conundrum of Maggies + subwoofers.
@mijostyn -- thank you. I've spent a couple hours now learning about dsp, with particular attention to MiniDSP. "Idiot proof" is apparently what I need. I'm definitely interested. I will say that the explanations get very technical, very fast.
@jeenam -- I hear you on Rythmik, and the appreciation/criticism of REL. I've read both many times, and I know that Rythmik has a stellar reputation out here. I'm going to look into them more, definitely. Thank you.
@sns -- yes, certainly, 95% of the time that philosophy is just exactly what I want. My experience with subwoofers is very limited but I'm inclined toward a pair as well. I know that the T/9X isn't really big in the world of subs, but I still wonder if a pair of them would be too much in my small room. (Also ... small budget.) For what it's worth, REL recommends the T/9 (single or double) with the 1.7is, the S series for the bigger Maggies.
I've been smiling about @jjss49 's suggestion to get the T/7s and "be done." I know he's right, at least in the short term. But part of me wants to let this percolate a bit, try a few subs, bang my head against the DSP wall, and enjoy the ride a bit longer....
Again, thank you all!