Numbers? Or not?

I'm debating whether or not Sphere/Element combinations should have a numerical rating as well, in the tradition of standard RPG attributes, or whether the system should be completely verbally descriptive instead of using mathematical comparisons. It's not necessary when dealing with angel versus mortal interactions - angels always win - but there is obviously an opportunity for celestial beings to conflict in a meaningful way, and there needs to be a way to resolve that.

Thoughts?