Success formulas for spells and thievery?

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?

This is supposed to be pretty opaque. The basic rule is that success is a function of comparative TPA or WPA. For more difficult operations, you need this advantage to be higher to ensure more consistent success. Player experience has given some very general rules of thumb. For example, my own experience is that for consistent success with propaganda, ignoring CS or WTs, you need 4x enemy mTPA.

There's also another side of this, which is that for easy operations like intel, the randomness factor seems to allow success even without a TPA advantage.

I guess I'm ceaselessly surprised at where opaqueness tends to appear in this game when so many things are laid out clearly in order to play the game well (or properly). Anyways thank you.