Yooper,
Hard to tell from the pics, but is there a wall/ceiling intersection above your center channel that's the same height as the one over your chair? I'm wondering whether it would be best to place the 45 degree wall/ceiling panel on the speaker side or the listening side of the room? Not saying it is, but Bryan, maybe you could chime in?
I also must sit close to the rear wall and I look at the wall/ceiling corner above me and think that it'd be a great place for a 45 degree panel as you have (I already have 3 242's vertically on the back wall that come within 18" of the celing, so the corner above my head is already somewhat treated, if not just interfered with). But then, I think that the opposite wall/ceiling intersection on the speaker wall (at the midpoint of the room) would really benefit, too!
I can see reasons why each approach would be good. Maybe both would be best!