I modified https://matplotlib.org/3.2.1/gallery/ticks_and_spines/multiple_yaxis_with_spines.html
to have a fourth data-set, like that: https://gist.github.com/AndKe/c0c999a22a8daebafb62171b671bf131
With the offset of “1.35”
One can get a glimpse of that, any less, and it will overlap, and more it will be invisible.
changing “right” to “left” does nothing.
Also, the resulting spines placement does vary with the width of the window. - from barely barely showing the third spine, to wasting space the wider the window gets.