Singing skill and Wind skill function the same way as far as helping with buff potency and debuff accuracy, except that Singing skill also affects songs cast with a String instrument or "sung" without an instrument equipped, whereas Wind skill only affects those songs cast with a Wind instrument. Furthermore, for the potency of the buffs (most notably Marches), the tiers work by combining the Singing skill and the particular instrument skill.
My thoughts and reviews
Lady Jinte wrote:
Vlorsutes' Negotiation Skill rises 0.2 points
Vlorsutes' Observant Parent Skill rises 0.3 points
Vlorsutes' Argument Diffusing Skill rises 0.1 points
on all sorts of sci-fi stuff...and things.