I wonder in multi-effect spells how are the priorities of arts decided, and by arts I mean the projectile, hit effect, cast effect, cast sound, and menu display object. I know in Morrowind all effects keep their arts and in Oblivion the effect with highest cost takes precedence, but in Skyrim it seems to be much more complicated.
I'd guess the first effect in the list takes precedence, and if any art is missing, the next effect takes the place? As for the shaders, it seems like they all apply and take turns to display?

I know I can test this out myself, but I'm hoping some experienced nice person could just tell me the answer:)