Thanks PopDisplay, for fulfilling my request to continue via thread, instead of PM. I'm sure you don't mind if I paste a part of my response here, so that others may piggy-back, criticize, and/or add other salient points.
1. Sound isolation can be welcome for certain setups, but please note this is a very, very different thing than acoustically treating a room for unwanted reflections.
2. Your room is huge. The 605, while an excellent value, would not have a snowball's chance in hell in my own setup. When the display gets larger, the volumes go up accordingly. I know that sounds weird, but when you have a 50-75 sq ft display, your instincts will be to have volume to match. Then again, the need for power will depend on:
- volumes desired
- speakers' sensitivity, nom impedance, min impedance
- distance seated from speakers (SPL decreases EXPONENTIALLY with distance)
3. The RPTV's constraint on the center placement is something you just will have to live with. The important thing is to understand the compromises, and then reduce the number of them. Almost nobody can succeed with a "perfect" setup. I also a horiz MTM way too close to floor, but I placed it on a nice acoustical panel to help out a bit. Do I suffer quite a bit still? Yes. Did it help? Yes.
4. According to BMXTRIX, the screen will be wavy in about a year. However, if it works for you, the High Power screens such as made by DaLite are much stiffer and more resistant to waving. And even with waves, they disappear much better than with others. I use a 159" pull down manual HP dalite.