"Plus, for the 6 channel stereo mode at least, along with an increase in hiss (in my rear center at least, I don't have the other 3 channel amp on), I also get a accompanying increasing in buzzing. (Now I remember someone else mentioning this.)"

Kevin - I'm hearing a buzz/more of a whistle in 5 channel stereo mode. I posted this in the other thread. Not sure what it is.

Your comment about "interaction" amongst you amp/speakers/950 is valuable, cause I really belive this, to a large extend, is whats causing so many discussions on the 950. Appears some simply might have faulty units (those hearing hiss over source material - your rear channel might be included here, but I assume its pretty close to your seating area, and my front center is my worst hisser), but playing around/trying different things may improve things. Isnt it kinda like "tweaking" everybody loves doing that:>