OK - I have several reasons for asking this - the bigger the force, the bigger the area affected. Seems reasonable to me. What do you think?

Well, that's pretty resounding, isn't it? You ask a question, get the answer, then try to vote to change it to what you wanted the answer to be...

Is it so strange that radius is determined by magic rating, but power is determined by force? Your magic rating says how far you can spread the magic, while the force says how nasty it is to be affected by that magic.

JaronK

Heck no, the size of the area is determined by the power the mage has available, the force just determines how effective the spell is, not how large.

Canon is canon for a reason. I like the radius as a guage of raw magical power and force is how concentrated you choose to make the spell damage.