listening99 OP
The "bleeding" of information from one channel to the other, is what I'm seeking to understand - how does this impact sound-stage?
The more you bleed left and right towards mono, the better the central image becomes, and the worse the image either side of center l & r and out side the speakers image becomes.
Vinyl is classic at giving a great central image at barely 30db of channel separation at 1khz in the midrange, but it's bass is almost mono, and it's treble isn't that much better.
Here is a expensive Lyra phono cartridge channel separation graph.
https://ibb.co/3Y9jM2W
I did an experiment for an audience on the output of a cd player to bleed the both channels down to 30db max, with a switchable circuit, and everyone preferred it playing old Beatles etc etc. Because it gave more richness to the mix, even though it was almost mono'ized and only had a central image.
Cheers George