I like the center tower suggestion. I'll look into that. It can still be a clean look that way as well.
The center channel will be permanent & will not move. The shelving idea is a viable solution that I'll definitely look into as well. These are all great suggestions & I appreciate it.
I already know that the sound quality is already going to be subpar to what I'm used to simply because of the exposed concrete ceilings, hardwood floors & abundant windows.
With that said, the aesthetics are more of a priority for me. Then making the best sound quality I can with what I have, secondly.
This is just my opinion, mostly on the idea of the culprits behind a bad room/setup. I personally think there is too much credit given to concrete/glass/hardwood as far as making or breaking a setup. Really, I do, and I have double digit panels weighing hundreds of lbs. IMO, the PLACEMENT of the items in any given room, whether glass/concrete, or comfy/cushy, is what really matters. After all, a rug or curtains ain't gonna do jack for anything but for really high frequency, and even then it's not broadband, but some random subset of that HF range depending on the fabric.
What I find just destroys intelligibility sometimes is with a speaker that is too close to a boundary where midbass gets excited, gets bloated, and masks the dialogue for example. So with that in mind, if going with a tower idea, may I simply present the idea of a thick tri trap directly behind it. You won't really have to worry about sidewall reflections so much, particularly as they're flaring out at 45 deg. If you think it's horribly ugly, forget it of course. You can have a custom print made, or perhaps ask for stock samples (see which matches your paint the best in person), or even go DIY, cutting fiberglass wedges, and covering it up with a custom design of your own making. Just something to throw out- I think that would make much more of a difference than worrying about concrete/glass. Again, JMO. Here is an example below, and of course you don't want a rear ported speaker if putting the speaker flush to the panel (which is perfectly fine to do otherwise, AFAIK).
GIK Acoustics Tri-Trap Corner Bass Trap - GIK AcousticsAcoustic Panels | Bass Traps | Diffusors | GIK Acoustics