Huh, at some point in the last month the wiki's been updated to include formulae for the vigoras/vigorous weapon skill*. It's got exponents and square root involved, so no, not gonna calculate in my head. At least the table has the relevant bonuses for medium skill lvl 20.
Also, with the introduction of the special attack frame, vigorous has been folded into that. Tentatively, the ousei (technically also vigorous...) type buff is also listed under special attack. I don't think many kamihime have that type of buff yet, but the main example is awakened Brahma's burst effect.

*if vigorous is new to you, just think more bonus damage the higher % of HP you have left. If you really don't like Pride, then this is the thing for you.