Hi Bryan!
I have been in the same place like you 3 months ago. Building and calculating diffusors is a very complicated thing, so take your time with it. It is not enough to just buy a good diffusor and put it into the room.
You may ask RFZ_Quest (Paul) directly, I'm sure he will help you. He made a new topic about diffusors and building them:
https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1233352097Read all of the links Paul gives. It's worth it.
Although, if you want a good advice, don't waste your time, money and ears on Stereophonic music reproduction. Ambiophonics give you a liver sound, and even improves the sound quality. Especially; you don't need any diffusors nor absorbers (They help, but only make a minimal unnoticeable change) Please visit the topic here:
https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1236624896Go to
www.ambiophonics.org to find out more about ambiophonics.
Kindest Regards,
Wolfgang