Great review, I have one suggestion, try adjusting the center angle higher or lower to see if that helps with the off axis, a few inches off axis shouldn't matter that much unless you are quite close to it and with that size of screen I know you are not. I also run the center 2-3 db higher just to make the vocals more pronounced, it really helps.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70