I was able to at least test my landscape-solution in 561 (rebuilding the nanite landscape still makes pieces go missing) but the upgrade into 561 worked and I was able to run the standalone.
~25% increase in performance 554 vs 561. Even better, the dips in fps were less impactful and increasing the density of landscape-grass and/or the cull-distance cost much-less per unit increase vs 554. Bugs aside, a decently-solid increase in performance.
554
Looking out, on that mesa/plateau, the bright spot top/center is another Quinn mesh; 45ish fps
~55fps looking down
Increasing the cull-distance for grass from 1 to 2 (double the radius) only cost me ~1fps in 561 vs several/10+ in 554, so another solid-gain.
It might still not be optimized, but a good-gain is a good-gain.
NOTE: the rendering didn’t change, between versions, I just futzed with the color between tests.