Well the enclosure was built out of 2x10" boards. I allowed for about a 2" air gap b/t the back of the center channel(and port) and the back wall behind the speaker.
Also, I did not make the sides of the enclosure go all the way back against the back wall, so that there is air flow/escape all around.
Finally, I buil the enclosure leaving about 2" on either side of, and top of the speaker with the intent of stuffing some 2" mineral wool panels between the speaker and the inside of the enclosure. I am thinking (hoping) that this may mitigate any negative acoustic impact of the enclosure to begin with.
Any cont'd opinions on my design, and my rationale explained in this post are apprecited.