Questions: Dispelling Powers & Conflicting Effects

To dispel a power of a creature of Might, you treat the power as if it was a spell of a level equal to the creature's Might. Cool.
What about a power wielded by a character, through a supernatural ability? I read what the Penetration is, but I couldn't find what the level is for dispelling.

Also, what happens if two spells of with conflicting effects affect someone at the same time? Say a person is made happy by Magus A and then made sad by Magus B, both with a Sun duration ReMe spell. Now what?

I hadn't noticed that before. After ten seconds of reflection I think that it is quite cool.

I couldn't find it either.

The target is both happy and sad at the same time, it's roleplay-o-rific. However in situations where an accomodation really can't be made I'd go with the higherlevel spell winning or alternately the higherbase level spell depending upon if I was comfortable stopping to game to spend time back-calculateing the base level or not, (that'd be a not 9 times out of 10)

I think I will set the "level" as the Ability roll. That should make it fairly easy to dispell in comparison to a Hermetic similar spell, but not as trivial as basing it on "0 Might" or "Ability score". Setting the level to Ability x 5 seems excessive... doesn't it?

Yes, that sounds like a good solution.