So how does dual casting work exactly? How much more damage/duration/ effect and how much more mana? I'm trying to figure out if it's worth it. I'm running Ordinator, Odin, and Apocalypse. How is cold overall? It seems to have lots of resistance reduction, but I noticed the automatons don't seem to give much of a fuck about it.

All the fire spells say enemies on fire take more damage. Is that different from the 15% chance of ignition from the perk tree? It seems odd for the text on the spell to be completely dependent on a perk.

Do the Powers you get in some of the perk trees give experience to their skill trees? I think that was my last question.