I was reading through the guide again for old time's sake having not been around for some time, and I suppose that the "formulas" section isn't technically part of the guide, but in a game like this one it's hard to imagine how to play it well without a decent sense of transparency.

Anyways, with regard to offensive spells and thievery operations, all the formulas section has to say is this.

"The ratio of your WPA to your opponent's WPA will determine the success rate of your conducted magic spells."

And that's it. There's no actual formula that provides WPA ratios and examples, or spell-level difficulties, or anything. Is there any information available anywhere that gives a good and proper sense about what determines success or failure?