There's no hidden way unfortunately.

One concern is performance, these overlays aren't very optimized because I was under the impression they'd be shown 1-2 tops =) I might need to do some optimizations especially on the sphere ones where they draw hundreds of lines. We'll see, first I have to do the feature to see if lots of them are even a problem.

But as for a way to do this, I'm thinking either:
- button in terminal (bottom right not in the center, because that is already cluttered... or maybe at the very end in center... I dunno) to turn on specialized overlays only for selected blocks and persists until you click it again in terminal or you go out of range of the collective blocks.
- shift+R could be a toggle per block, a bit more manual than the terminal way but might be able to spin this off faster than that, not sure yet =)

Both ways sound good to me, glad you're considering it. ^^

If it does turn out to be a sizable performance hit, that might be acceptable imo as I would only briefly turn that feature on during the design process and not fly around with it in regular gameplay