Nice job on your posts - great detail. I own the same speaker as you know. Three things come to mind,
* Get two packages of Fostex sound reflectors and place 3 in each upper horn and two in each lower. These will stop, I mean stop, your roon overload issues. Email me directly or call for placement of the reflectors.
* Try Paul Speltz's anticable for $10 foot. Money back 30 day trial. You must put this on your Cain's. Ask Terry about this also. Huge step up for very little money.
* Place only one approx 1 inch thick and 8 inch X 6 inch square piece of Dakron in the upper horn sections right behind the drivers. Yes, reach in and play!
* Get a Wright Sound preamp. Use the high gain setting and your system will make you cry over the music's emotion and depth. I am getting wonderful depth.
* One more important thing. Get them off your floor. Isolate them by placing them onto a 2 inch thick maple board or concrete paver. I place those little discs on the underside of the pavers/maple boards so the plateform slides easy. I can then move the speakers back when I need the space for guests or for placement tweeking. These are the same discs advertised to place under piano's for moving/sliding around. This will greatly help reasonances which fuzz your sound now.
I love these speakers. My speaker set up is like yours. I am against the back wall with Echo Buster sound panals behind me. The speakers are 5 feet from the wall behind them however. This greatly helps depth. My room is 22 feet long so I sit about 16 feet back from the speakers. 8 feet apart and toed in slightly. Your right-on about the impact of toe-in.
I am sending you pics.