I apologize, but since the beginning of this thread, myself, my wife and my 2 year old have all gotten sick.
I haven't had a chance to really go through all of this info, yet.
From what I can tell, it has matured into a conversation, which is outstanding.
Forgive me if this has no basis in what is being discussed, but it reminded me of a graph in "Acoustic absorbers and diffusers: theory, design, and application" By Trevor J. Cox, Peter D'Antonio.
It's on page 34 in the chapter Application and principles of Diffusers.
Acoustic absorbers and diffusers ... - Google Books
Is this graph kind of what we are talking about, or is this only showing first reflections?
When I am back at work and have the time to go through everything, I'll be able to contribute something more to the thread, I hope.
Thanks,
Seamus