There isn't better document, sadly. One of the last things I was working on before time ran out was some tutorials through Toasts, which you probably saw in the editor. It does sound like you figured it out in the end.
I agree there's some confusing values in some of the components available to the editor. It's something I want to clean up. If you look in the 'Trolltown' level, you see a similar bit of confusion happened with the Fireball scroll, which has a range of 3, and a radius of 7(!!), so obviously things aren't clear enough.
I played and beat your level, it's a neat concept, though it took me a minute to figure out what you wanted me to do. Heh. What was the second key for out of curiosity?