My area is about 15 x 18, about like yours but attached volume gets up to about 5K
Already having Klipsch almost everywhere. when the older Rc3 I was using for a center seemed to be croaking, I found a killer deal on a new G-28, about $250.
It fits right in.
AS a center that comes in over the top of my Mitsy "73, my extension arm lets it sit in the same plane as the mains, F-3's all about 26 inches from the front wall. and at the right angle WRT to MLP. which is about 11 feet from that front stage plane.
I'm very satisfied with the way my Onkyo 818 puts the the front sound field together when I run LCR and subs.
What would you be using to create as much integration of the inwalls with this speaker?
Would you go as simple as using an SPL or can your receiver already have some speaker setup, some flavor of Audyssey or etc.
And then there's the question of movies, games,and music. and how YOU like it
and once you start putting xo's at 80 hz, it gets into what you like about what you hear.
It also looks rather cool . . .