Hey Minnesotafats,
As I have been thinking about this, you must have the patience of Job!
Experts, even as incredibly talented and dedicated as Jeremy - based in his amazingly consistent work at getting “best of show” sound every time he exhibits, cannot
predict what will sound good.
If it were me, and I perfectly understand that this seems like a shared living space and your situation is different than mine, I’d run out to Home Depot and get 10-15 bales of insulation.
You can move the insulation around to prep for his visit to determine what will be more natural…. It may not be perfect, but will definitely reduce the echo chamber phenomenon in the mean while.
All the best