Dusting this one off a bit. Still looking into my options and had a thought. Instead of using OC703, would using 2'x2' acoustic ceiling tiles work instead? I was thinking of placing two tiles, (one on top of the other) as an alternative to using the OC703 and then framing around them.

If you look back at my first post, look at the ceiling in my pic and that's what I was thinking of using.

Thoughts?