I think the expander device would greatly benefit if it were to have a distance guide input. The internal distance parameter would be the max distance, and the guide, being a height map, would then have white for max distance and black for 0 distance, determining per pixel how much it should be expanded if it were to be expanded at all.
I’m not entirely sure how the expander device is implemented and if variable distance is an option, but it sure would be really cool if it were possible.
Also would be nice if it gave more feedback whilst building.