Acoustic Geometry Ratification

Here's a video which doesn't seem to mesh well with some of Ethan's findings:

youtu.be/akiWq97dSBA

Specifically his use, and type, of diffusers at early reflection points, his treatment of the front wall and putting thin, flush-mounted absorption in the corners rather than bass traps.  Also he's put diffusers in the rear corners and just one small curved diffuser behind the listening position.  

I liked his visual acoustics video but this seems a bit misleading.  

Just thought I'd put it here for critique.  

Thanks, 

-m