flop out a rune of power
build 6 stacks of AB
press alter time and continue with 3 more arcane blasts
just before the time reverts, after the 3 Arcane blasts (sometimes 2) depending on proc's and buffs for haste; finish with your 2 stacks of arcane missiles
now your back to 6 stacks, all your current buffs and can bust out the two arcane missiles ( making 4 in a row) then burn down your mana to 230kish and then mana gem.
I know this probably isn't mathematically the best, but doing this has easily given me the biggest dps. i used to pop everything at the 6 stack before alter time, but with little haste this only works well with hero. ( that is if you mastery stack hard )
how do you guys bust out your alter time?