Brett, if you haven't already done so, get Audacity, and Room EQ Wizard. Audacity has its own site and you get REQW by joining Hometheatershack (free) and then downloading it. It's a little harder to use with the Radio Shack SPL meter, but it can be done if you don't have a measurement mic. There are more sophisticated (read - you gotta pay for 'em

) tools like TrueRTA and Audiolense that all make for a powerful toolkit in supporting digital RC.
My feeling at this point is that Inguz works pretty darn well, but I'm getting the feeling any kind of RC probably works better for "typical" (front firing) speaker designs than it does for my kind of rig. However, I think once I get past some of the current complexities I think I'm going to keep it in the loop.