With my room setup, the posters in front, and the posters on each end in back (the 5 poster row) are used to cover in wall speakers. I did place the Roxul around the speakers, and not covering them obviously. The remainder of the posters are full Roxul. This is my first home theater, and still have much to learn about acoustics. Perhaps in a few months, after I get a chance to enjoy the space, I will have to start reading up on acoustic properties and learn on where to place my acoustic panels to optimally perform (More time on the forum!). For now, I just wanted to get them placed on the walls pending arrival of my furniture.
No offense taken - I am a newbie to this whole thing, and am starting to realize that a home theater is not something that is ever completed - you will often be looking for the next thing to improve on and take it to the next level.