Re: magnitude, but asking about the force/quality factor
What kind of tier/force is a power that watches someone? Seems like 0 since you don’t actually affect them but it does help you. The examples for force don’t seem to account for those sorts of effects
I would ignore force and look at quality instead, with a magnitude depending on how detailed the info you get is (black and white visuals of just the person, sight and sound of the entire room they’re in, etc)
This is re: magical things. Quality seems to point at mundane things (with the exception of the ghosts, which I don’t actually understand), and I am not talking about a spyglass, more like a crystal ball. Also wouldn’t Scale seem to handle how much you can see, and Range from how far away?
Also.. limit testing. Let’s say Force/Quality is 0; does this spell/item see as well as “worn and tattered clothing” looks? So.. blurry, or with shears in the image? I could see that through a grimy window and a spyglass and probably loss a lot less/be much safer..
Say it’s 6 but the item doesn’t have the “unreliable” drawback; the quality seems like a complete waste there (since it is implied you wouldn’t roll Quality for effect when that drawback is absent).
My point is rating things like how you pointed out is not clear when magic or some arcane mixture is at work, so I thought some detail would go a long way. Even just a little more variety in those examples on p. 221 would really go a long way to understanding how Force should be rated in general, and especially for less common effects that my players will soon desire.
Try looking at the Rituals section, since that’s how you make magical powers anyway. The first sample ritual is Ghost Map on 223, which uses ‘quality of information’ instead of force for calculating the stress cost. That’s about as direct an example as you can get for scrying on somebody, and as a general case it shows that quality is perfectly applicable to magic.
You aren’t supposed to consider every single Magnitude category every time. Force applies when the power exerts force. For scrying, range and scale would be the main things to factor.
As the text says, the Magnitude ratings are there to help you ballpark a final level, not as a mathematical system to rigorously apply.