Good luck with that! I'm guessing she's got you figured out by now...
Speaking of diffusers I've been making my own using the bbc schematic.I got 5 of 8 done right now. Honestly they're more for aesthetics than actual acoustics. Two sets of 4 in groups-- each group having one each made from walnut, naturally grown heart redwood (impossible to get nowdays), pine and whitewood.
Awesome. I actually have a plan to make about six of them and tell my wife they are artsy wall decorations.