Tapestries might be effective with the very short higher frequency waves, but issues increase as you go lower in freq. Phase issues can suck all the mids and lows, and make things a tinny, hollow, mushy, mess.
Absorption is usually the solution for the very problematic lower frequency waves. A low freq wave at 100hz, has FAR more opportunity to have issues than a wave that is repeating 10 times as fast.
Every room has issues. If you want the dome loud? A lack of sound treatment isn't the worse thing. Sound treatment, or better yet, fans, will help the PA. I'll take a LOUD house, over a kind of loud house, where the PA sounds better with less fans, ALL day, Every Day.
(I prolly would have installed the speakers in a more random pattern. ALTHOUGH, they may have at slightly different distances, AND curved them all(they did) to address reflection issues)