Thanks! That’s a great summary of a useful technique.
In this case, the minimap is for use in the World Partition dialog panel in the editor, so I’d need to take the output of your technique and place it in that role. (Given that we have full source code, in theory I should be able to discern how to do that through code inspection.)
We had an in-person collaboration gathering last week on a different project, so I’ve been away from this issue for a few days. I’ll be getting back into it in the coming days.