Great point, thanks! I've updated it to CC BY 4.0. I'll think about whether I can clarify the armour rules (I tried to keep the document really lean to make it easily printable).
Well, if you can't find a clearer way to explain it, a short example might help with understanding.
Just uploaded a new version that hopefully clarifies things (and also fixed a typo in the spell Parametrize). Thanks again.
