@pindac,
I agree with your assessment. There is nothing more satisfying than experimenting on your own and realizing the benefits of tweaking things here and there to realize greater outcomes.
For my own personal philosophy, I have learned through trial and error that I much prefer to have strategically placed diffusion along with some absorption products to balance the room. I use old school Test Cd”s, Radio Shack sound pressure level meters, Rives Audio Professional audio test measuring kit, and a PAA audio measurement device. However, my ears tell me what is good overall, no matter the measurements. These tools are guides to help one understand the audio environment where you will be listening. Also, if I decide to use subs, I use a Velodyne SMS-1 sub EQ which is plugged in a tape loop on my Octave Jubilee preamp.
I much prefer reverberation and ambiance over a less dry and less reverberating sound field.
Can you please share your a sampling of your DIY acoustic controls? Would be interested to see what others are doing.