Hi all. In typical net pattern, responses have ranged from helpful to snarky, extending to rejecting, spurious to critical. And, also in a familiar pattern, along the way my original question was blunted and redefined. But I'm quite appreciative of all the advice and opinion. To sum up:
1. It sounds like removing the components from between the speakers CAN have some positive effect on soundstage and precision.
2. It also sounds as if that effect is worthwhile only in conjunction with other diffusing, absorbing, and deflecting strategies and techniques.
3. Since I do listen to my turntable about 65% of the time, one of my reasons for inquiring about the side placement is to give the tt a more stable base than the top rack of a Salamander stand not really designed for a 70 lb turntable.
4. However, even to experiment with a new placement I'll have to buy longer speaker cables. I don't know if I want to make that investment if I'm going to be marginally, at best, happy with any sonic improvement. I could buy used and then resell, of course. Much of the fun of this hobby is trying new things.
5. Holistically, my listening room/basement doubles as a laundry room and an ersatz kid play area. Yes, I've decorated and furnished and lighted it enough to demarcate it from the rest of the area, but with its small size and low ceilings, it's definitely not ideal. And, as noted above, placement options are limited. The maker of my speakers suggested I place them along the long wall of the room, but that's impossible what with utility room and closet doors, etc.
6. I'm a music-to-color/pattern synesthete. That is, when i hear pitches and chords and notes, I see colors and patterns. Thus, very few concert light shows are ever "correct" for me :) And so when I listen to good recordings on my system, it's a sidestage visual experience alongside the mainstage aural experience. When I discovered hi-end audio, my visual side suddenly became more pronounced, more clear, more palpable. And so I make any affordable tweaks or changes I can to see what might happen. This is all drug-free, of course. Well, since 1997.
7. I think I'll keep the components where they are - and maybe move the de Capos out another 6" or so -- and play the new lp reissue of Steve Reich "Music for 18 Musicians" and be happy with music and colors.