Someone on steam released a magicka tool complete with gui to set your own spell hotkey. It's pretty good and fun to play around with. Here's the link to the thread if anyone want to check it out: Link
d/l & install it. Copy the code below into notepad, then save it as Magicka.ahk & place it in your game folder. You can use autohotkey to edit the spells as you like or use notepad & then save it.
;#UseHook ;Script may use Hooks ;#InstallKeybdHook ;Force the use of Hooks SetKeyDelay, 50, 50, Play ;Delay between KeyDown/KeyUp and different Keys ;Now for the Spells: 1::SendPlay qrqrqrqrqr ;xIce, I just like it ! 2::SendPlay qfasa ;Thunder Bold 3::SendPlay fdfqdf ;Meteor Storm 4::SendPlay fqffqffq ;Conflathingy 5::SendPlay qqf ;Rain 6::SendPlay asf ;Haste