Thomas, Re your question about set up - If you are talking about setting up the Maggies you would want to set them up so the back wave would hit a wall behind it, something you could control the acoustic nature of, and you would want them, ideally to be 5' from the wall. The wall's surface would be ideally broken up with diffusing materiels, There are all kinds of tricks with panels that will work - one thing I have done is to set the speakers up close enuf to a side wall that so with a bit of toe in the back wave hit the side wall and then hit the wall behind the speaker. Just something to remember and try if you.
Setting up front firing box speakers in front of the open space could work, but I still like them in front of a wall with the open space behind me for a couple of reasons. One is that the open space breaks up the reflection from the side walls (which would hit a solid wall otherwise and give you reflections from an additional surface) and could result in a cleaner sound.
Re the room with the side walls and pitched ceiling. If you set that room up, and you could, I would have to set the room up so that the speakers fired down the lenght of the pitched ceiling - you do not want to fire into the sloping sides. Also, if you want to maximize imaging potential, you would want to be sure that the speakers were set up so that the middle was directly under the center of the pitched ceiling and your chair also. That way reflections off the cieling would be identical and not screw up the sound stage. BTW, I suspect I would not really enjoy panels in that room, but you can try if you've got'em and see what happens.
Setting up front firing box speakers in front of the open space could work, but I still like them in front of a wall with the open space behind me for a couple of reasons. One is that the open space breaks up the reflection from the side walls (which would hit a solid wall otherwise and give you reflections from an additional surface) and could result in a cleaner sound.
Re the room with the side walls and pitched ceiling. If you set that room up, and you could, I would have to set the room up so that the speakers fired down the lenght of the pitched ceiling - you do not want to fire into the sloping sides. Also, if you want to maximize imaging potential, you would want to be sure that the speakers were set up so that the middle was directly under the center of the pitched ceiling and your chair also. That way reflections off the cieling would be identical and not screw up the sound stage. BTW, I suspect I would not really enjoy panels in that room, but you can try if you've got'em and see what happens.