Looking at your room width, I'm wondering if you want your couch/seating that far from the screen to begin with. How wide of a screen are you planning? Assuming you would have something less than 10' if you plan on some borders on screen sides (let's say something closer to 9' or 108"), if you look at recommended seating distances using following chart (say 1.21W for example, that would put you at just under 11' eyes to screen. Some further consideration on this may make your center/nulls issue less concerning.