An idea for a new reference element that forces the
CE extended change to become something with empty space, instead of not overwriting at all. Before this, you could use CEs that change into empty space after 0 frames, but I think this would be easier.
Example: (C = CE1, e = empty space, R = rock, F = forced empty space)
CE1 changes into [empty] after 5 seconds.
Extended change target: (replace when destructible)
The above would not overwrite the spaces above or below itself. This following should overwrite the spaces that are above of below itself into empty space:
CE1 changes into [empty] after 5 seconds.
Extended change target: (replace when destructible)
I hope you get it!