I agree. I have five 86″ 845’s free standing in a ITU alignment arc for 5.0 channel surround listening. Each panel has a two inch wide woven nylon strap fastened to the panel center top, and attached to the ceiling one inch above to prevent tipping. The panel bases are sitting on two inch blacks under the panel vertical side members. There is no perceivable or measureable structural resonance. The membrane resonances are spectrally well distributed and dampened, and far exceed any structural resonance.
I highly recommend this approach if one is fortunate enough to have a room ceiling height just a few inches higher than the panel’s length. According to Dr West, this has the acoustical effect of extending the panel’s dispersion length to much greater effective length.