I’ve seen Sheldon Brown’s lateral stiffness chart, but I haven’t seen lateral stiffness of different chain widths; that is 7/8 speed vs. 11 speed.
I suspect narrower chains flex more, but have never done, or seen, a comparison of the minimum lateral radius of new chains by width (speed).
That said, I don’t think cross chaining is as bad as once professed. With the industry promoting 1x wide range drivetrains, it will not cause an issue. But, as people have pointed out, most riders are not at the extremes for extended periods of time.
The one piece of data that I’ve never seen published, is the max chain angle. I roughly calculated that a cross chain is a little more than 2 degrees to a little less than 3 degrees based on 1x and 2x speed setups and cassette width.
The industry basically tells one person with a 2x, “Don’t do that” and another person with a 1x, “Do that.” But neither has provided any support for why those recommendations are made.
John