Listening to the copper set up I was noting the pluses and minuses. It was when I put on a solo cello was when I heard the grossest event. The cello was playing dead center and as it played, some of it went about 1/3 of the way to the left when it always stayed nice and centered.
I chalked that up to the stranded wire.
You honestly believe the location of an instrument shifted what, 10-20 degrees because of stranded wire? You do realize that makes almost anything you write suspect? Perhaps you could discuss how we perceive instrument location and how stranded wire shifted the image 10-20 degrees?
Are you familiar with Occam's Razor? ... the simplest explanation is usually the right one.
Did it occur to you that you had a bad connection that worked its way loose? It wasn't stranded wire that caused the image to shift. It may have been a bad connection. That could have explained the other issues too.