You start alter time with 2 Missiles procs already active. Missiles are the strongest spell and all of your procs and cds are active then.
Type 1: AMx2, ABx (based on haste), ABarr
Type 2: AM, AB, AM, AB, ABarr
Finally, if you get another Missiles proc during Alter Time, you can even use it instead of ABarr. If AT ending won't move you, the channel will not be broken either.
Thanks. And final question, since we typically want to stay at >90% mana, do we simply cycle AB -> x -> AB -> x, where x = {"Scorch", "Arcane Missles"} where you get the following spell sequences:
Scenario A) If 2 AM procs, AB -> AM -> AB -> AM Scenario B) if 1 AM proc, AB -> AM -> AB (another proc doesnt occur) -> Scorch -> AB Scenario C) if no proc, AB -> Scorch -> AB -> Scorch until you get another AM proc, then use that after your next AB
I'd imagine this is optimal because you wouldn't dip as much under 90% mana and you avoid overcapping on mana, which, at the end, presents the unnecessary use of too many scorches after dipping below 90%
I usually go AMx2->AB->ABarr-> and depending on what i have procced, cd's being used, alot of times you can squeeze that 3rd AM proc in after the Arcane blast that procced it and still get the barrage off at the very end
If you have two missiles procs, you always use one if you are either at 6 Charges or at 1-2-3 Charges *except* when you are building to the Alter Time burn time when you always save Missiles until 6 Charges.