Magic ball delay should be 0 and its contents should be this:
This is a puzzle from my unreleased levelset from way back when. Originally this used a fancy schmancy "when element enters the space below this tile, copy it to the space above" CE, and white keys to enforce the "you can only generate so many bombs" gimmick, but magic balls and growing walls do just fine here.
Unfortunately, Jamie, this is just about the cream of the crop. The other levels in this levelset are just the levels I've already released in this subforum, some standalone levels by other people that I imported individually, and about a dozen puzzleless CE tests. I do have a short tutorial levelset from 2018-2019 sitting at 8-ish levels that I haven't neatly wrapped up yet, though, so I may try working on that eventually.
Cool - give us all a shout if you get something finished. I'm always keen to find levelsets with decent puzzles and clever design. So many of the levels just use the random generator and have very little thought put into them.