Nick, you might want to think about 6 lightning.
Nearly all level 26-30 mages use it for twinking, because

1. It deals nearly the same amount of damage as a 5 fire
2. Its cooldown rate is much faster, so you can use it more frequently

Just take this into consideration.
Also can you manage to also have a level 25 int helm on? They require 55 int, and they add mana regen.
So for gear Shiv armor, talon, shield, level 25 int helm.