I my self have M80s in an all Axiom system similar size room 19x21x7.
I have everything along the longer of my walls, on the left portion is open to equal size kitchen on one side, bathroom and bedrooms opposite.
In doing so I find it helps, so as not to need to pressurize the rest of my suite or lose sound to the other rooms. As it would with entertainment center facing them.
Just try to avoid losing sound to other rooms or close doors if behind you when listening.
Being the on and in walls have less cabinet you may notice you need more bass, that a cabinet produces. Although if you currently find your SVS sufficient possibly not
