Workflow-wise I'm kinda happy. Geek-that-ain't-right is flaring wildly
Starting with no GR6 preset loaded, add components, learn MIDI controls. Everything working correctly.
Save a Studio One preset instead of a GR6 preset and everything recalls/functions properly in new sessions and songs. Managing presets via SO instead of the plug itself is definitely doable for me, but ...
This isn't right. It tells me that there is some kind of interference going on between GR and SO. I'll pair it down and report a step-wise recipe for both vendors.