Finally got all the parts up & running to play around with REW. Got the Minidsp UMIK-1 and a Mic Boom/Stand. REW latest version. Calibration file installed. Think I have everything done correctly. Now I just have to figure out what I am doing wrong.
I tried suggested settings on the plate amps from a couple of people, and I spent a bit over an hour just running the basic sweep from 15-20,000 Hz, Left channel, Right channel, and combined.
My results were constantly changing, which was expected. What was not expected was that I seemed to be unable to change the basic shape of the curves.
I was able to tame the peak at around 30 Hz by playing around with PEQ and Phase (etc - those had the biggest effect), but...
I have serious "suck out" from about 40-120 Hz. I couldn't boost those frequencies to save my life (yes, I mostly did it by getting the peak down as much as possible at 30, then turning the overall gain of the plate amp up).
This was about the best I could do.
*******Well, I tried to save the image, now I can't find it*******
Lets just say it was ugly. About +2 db from 25-35 Hz (or so), then - 10-15 db from 40-45 til almost 120 Hz with 1/3 Octave smoothing, both channels (each channel was similar, right channel not quite as pronounced)

Got tired of it. I'll try again tomorrow. Read about REW some more. Think about it.
No clue why the "Phase" portion of the sweeps was all over the place.....dropped to the bottom of the scale, then jumped to the top and started down again, only to repeat...
******Let me know if I should move this to another Forum******