Hi Phil, in my existing setup P17 QRDs cover the front wall, and P13 QRDs (in a 2D configuration) cover the first reflection points on the ceiling. And I love them!Very interesting.. have you tried it out.
Nice if pretty easy to get your head around ... quite expensive but may well be worth it.
At a simpler level I see the amroc guys are developing a more " pro version " for sale .. will also be interesting to see how deep it dives
Do you see yourself doing different diffusers as the location changes
In my future setup, I will be using P23 QRDs covering a sizeable area of approximately 3.5m (height) x 6m (width) on the exposed area of front wall [subtracting the L/R space (~30cm x 2) taken up by the double-damped gypsum sidewalls and damped-metal plate bass attenuation modules]. I'm still uncertain about how many/where/which QRDs to use on the sidewalls, however. As you can see, I'm still investigating and iterating.