Monster level up patch

On my very old, never finished hack, I intended to have (well, actually I did implement...) 3 levels of difficulty selectable from an event just before the opening sequence. The difficulty mode would essentially select one of 3 sets of monster stats, with (for instance) HP being doubled for regular enemies, and 10 times for bosses.

You don't happen to have that hack still laying around by some chance? Or some documentation regarding the selectable difficulty?
I've been trying to reverse engineer a Japanese hack recently that does this very thing, but it being Japanese it's that much harder, and today I've about given up. I'm very interested in alternate difficulty choice.