@signaforce, my journey with toes in and out has been fraught with frustration. I really do like my speakers but they can tend towards bright. I finally landed on a combination of equipment, cables, limiting music that exacerbated this and/or dumb luck to get to the point I find myself now, which is a good place. Early on, I altered the speaker footers to have the front much higher than the rear to point the treble up and over my shoulders. Slouching also helped 
. Aiming the speakers this way and that had impact, but more recent changes to better equipment and cables have thankfully calmed the treble impact. The wonders of ChatGPT and its synthesis of the knowledge and nonsense of the internet are interesting, and I might fiddle with slight modifications to gauge the impact. I learned it essential to have tape on the floor to mark the original speaker positions, much like leaving a trail of bread crumbs, in case trial and error leads to big errors.
@richardbrand, thanks for your input. The phantom center channel (removing my center speaker altogether) is a thought offered by a few, but thaving spent a great deal on that center channel and the notion of not using it bothers me considerably. Moving the center channel around is a huge problem, as that speaker cable is a shortie and there is no wiggle room to connect to the amp. I have other cables lying around, so perhaps for experimentation purposes a different position or orientation is worth a go. I'm hoping against hope my tinnitus, just like yours, disappears. Fingers crossed on that.
Per recommendations (thanks again), I elevated and pointed the center channel as much towards the listening position as possible, and during my listening session last night, with the volume up a bit higher, dialog and the overall effect of HT surround was better than ever. It's nice to be going in the right direction.