Here is the answer I discovered so far in my testing.
All charts taken with Dayton Audio OmniMic - No smoothing on any of the OmniMic graphs.
With the EP4000 amp, the black line is the best we could do in my room with a 15 hz tune on the caps with no audyssey, no HPF, and no EQ. The green line is the best we could do with the caps in a 20hz tune with mic2200 with hpf/subsonic filter at 20 and the mic2200 eq being used to knock down the hump at about 70hz. Again - no Audyssey engaged for either graph. The subs were facing forward for these charts.
here are the mic2200 settings when using the 20hz tune.
Since then a friend and I played with the Inuke DSP 3000 and omnimic a bit more. We discovered that facing the subs towards the room's outside walls is better for frequency response in my room. Using the builtin INuke DSP - we got a darn flat graph on my Captivator Pro pair with 20hz tune at his point -- Audyssey was still turned off, and the MIC2200 was out of the loop. This second freqency response graph is taken solely using the Inuke DSP with 6 bands of Parametic EQ applied and the INuke's HPF set at 20hz. I can't quite get rid of the little bump at 20hz, if I put a PEQ band at exactly 20hz much above about -1dB it lowers the FR below flat at 20hz --- and if I take off the HPF at 20hz I get a big bump around 20hz (subs tuning). If I have my choiced I'd rather have a little bump at 20hz rather than a little dip - so I left it where it was without cutting out any more dB at 20hz.
NO smoothing on this graph!
Here are my Parametric EQ, HPF, and amp settings on the INuke.
Overall - Thumbs up! for the Inuke DSP, and the OmniMic! I think the EP4000 may have a bit more power, but it isn't worlds different - I'll likely be looking to sell my EP4000 and Inuke after seeing the greater EQ ability on the Inuke.
Next I'll try the 15hz tune.