Wasn't quite sure I was gonna post this yet - I'd like to get some confirmation, but I'm reasonably confident in the new results.....
Went back to the basics of room nodes and the rules of 1/3, 1/5, 1/7, etc. Moved the speakers closer
to the front wall so that the center of the face of the speaker is roughly 42.5" from the front wall - 1/5 of the length of the front to back (partial) wall. I'm now just under 10' from the front of the speakers and they are about 8' apart - roughly 3' from the side walls. Angled to cross right at the primary listening position. Remeasured.
This is the part I'm still waiting for confirmation on - how accurate is the RS Digital SPL meter?
I remembered there are issues, especially at low frequencies. I found a whole bunch of "correction" tables for the Analog version, so I'm not sure if the Digital is exactly the same.
This is the correction table I used: http://diyaudioprojects.com/Testeq/RadioShack_33-2050/33-2050.htm
Anyway, my frequency response for both channels using the AP Soundcheck2 CD is now +/- 3 db from 25 hz -over 8khz, and only down 5.5 at 20 Hz.
I seem to drop pretty bad starting at 8 kHz - too dead of a room?
Ah well, much happier with the measurements at any rate.
Imaging and focus good, Soundstage - Very wide and coherent (no obvious speaker location).
I will keep things as they are for now, add some OC703 2" in the corners behind the book cases and to a couple of other locations. AQD-1's in between the speakers on the front wall (with OC703 just to the outside of that - potential front wall first reflection point), and some more OC703 on the first reflection point of the sloped cathedral ceiling.
I'll take more measurements after that and see what, if anything changes, and hope for improvements on the other things (DEPTH). Have to get a different soundcard if I want to try to use REW.