heres the macro I use on my mage, it does use castsequence so that will lower the DPS a bit, but I just like seeing arcane missiles

#showtooltip Arcane Blast
/stopmacro [channeling]
/use 13
/use 14
/castsequence [target=focustarget,harm][] Arcane Blast,Arcane Blast,Arcane Missiles,Arcane Barrage


You can take out the /use if you have trinkets that dont have use: parameters. The x2 ab's does eat mana a bit, and I generally run with mage armor when multiboxing (molten when raiding/solo).

FFB is still a tiny, tiny, tiny bit higher dmg in top raid situations, but for a lot of movement intensive fights and fights where you can go nuts near the end (Thaddius, Loatheb, Malygos, etc) just spamming AB while going oom really can put you on the top.