For my Arcane Mage i did a 4 Step macro , just to help out with timing issues.

Step 1 /castsequence [nochanneling] reset=combat/alt Living Bomb,Arcane Blast,Arcane Blast

Step 2 /castsequence [nochanneling] reset=combat/alt Arcane Blast,Arcane Blast,Arcane Blast

Step 3 /castsequence [nochanneling] reset=combat/alt Arcane Blast,Arcane Missiles,Arcane Blast

Step 4 /castsequence [nochanneling] reset=combat/alt Arcane Blast,Arcane Blast,Arcane Missiles
/cast Arcane Power
/use 13
/use 13

again it worked out not too bad with average gear, was able to get 35-45 dps