These values don't really help me in practice. Personal experience is useful, but there isn't that much of it, and even with it, you don't always guess correctly. And how to apply these values to the specific defense of an object is even more unclear to me :confused:

You take the value of the object (or the sum, if there are several objects), divide it by the value of the monster, multiply it by the zone coefficient http://dreamcatcher.metroland.ru/templates/intro.html, and there's also a tricky coefficient that takes into account the random spread (this is for Vika).
The problem is that the spread turns out to be quite large, and also that no one knows the value of some objects (like hiding places, for example).

To train the skill faster, I tried to guess the number of monsters before each battle, and then checked the result.