Fluttering flames with dual casting is actually more powerful and magic efficient. It just doesn't kill things as fast as casting singly with both hands because you can stack double the 'Afterburn' on at once.

Dual casting is more efficient in this case because it also multiplies the afterburn damage which is the majority of the damage when you flutter the spell, repeatedly applying the afterburn.

Also it's x2.2 the magnitude for x2.8 the Magicka for dual casting :)

!!! 

OK, that tidbit is definitely going into the build (with credits given).  Hopefully in the next couple of days here I'll have the time to make a few adjustments:

1. mention cloak-increasing awesomeness

2. add some Alchemy recipes

3. see if I can get some numbers into the build in terms of spell damage

Great build man, i'm trying this one out right now. Always felt the destruction was a bit lacking, i think this build will make me like it a lot more.
One question though, any recipes you specifically recommend, or just the standard magic/destruction boosting ones?

I plan to get some recipes added to the build over the next couple of days, but for now I can say that my primary potions were Fortify Destruction and a special blend that gave me weakness to frost/magic but had enough positive effects to count as a potion (so I could drink it and thus strengthen Blizzard).  Can't remember the details of it right now, but I think Taproot (and Salt?) may have been involved....

I wish we could name our special potions in game...

I completely agree.  I've seen many builds that give particular potion recipes very cool names, so for awhile I thought it was possible to do so in-game, and maybe I was just missing something.  But nope, sadly.  

Yeah, I'm just realizing that now.  Alchemy seems to be the true mage crafting skill.  Enchanting can be very powerful, but in a fairly boring way (reducing casting costs, increasing resistances).  Enchanting seems more suited to hybrids - characters who use weapons and magic.  

You can use Fortify Enchanting Potions plus Ahzidal's Equipment to get enchanting boosts as if you had 5/5 Enchanter.