My preference in my current room is to have no stuffing, with absorption acoustical panels behind each speaker, and then QRD Diffusers in front of the absorption panels. Have the same behind the listening position.
I never have the itch to get up and move or replacement anything, so I've found the balance in my room.
I tried early on with different amounts of stuffing / closing the midrange off completely, but didn't like how direct the sound was, and missed the atmosphere / feeling of the recording. I feel the acoustical treatment balances everything out in my room and each recording / sound brings its natural unique characteristics.
You might find better results in moving the speakers / listening position or moving around acoustical treatments, than just altering the stuffing. All of these things alter the sound, and maybe they all need to be tweaked a little to get the perfect combination in your room.
But damn, I love these SoundScapes!
