I'm an Orc with the tier 13 4-piece bonus and I have the following questions:

1. When’s the best time to press the first combustion in a fight? After 10 stacks of the 2-piece? When the dot will be big?

2. When do I press combustion the rest of the time? I’ve seen number estimates on Combustion Helper from 5k-35k/tick. What should be my strat here?

3. I’m told that after the softcap for haste, I should stack crit. I’ve also heard mastery starts to play a roll now. Is there a point where I should worry about mastery for fire now?

From what I understand, Dragonwrath, Tarecgosa's Rest replicates every damaging spell that is cast only the copy is in the form of arcane damage instead of fire, at least for a fire mage. In the past I have observed that in World of Logs this is displayed with two copies of each fire spell a mage casts, one of which does 33% more damage than the other. I understand that the larger one is the true spell being cast and the smaller one is the arcane copy created by the staff.

My question is, why is the larger spell - say, Fireball, Pyroblast! or Scorch - exactly 33% larger? I can account for only 28% of the difference in the damage done, with 25% the bonus from Fire Specialization and 3% of the bonus from Fire Power talent. Even if they add multiplicatively that would still only result in +28.75% damage, not +33%.

What have I missed?

I wish I could post a link to show this discrepancy but it appears that World of Logs is no longer showing two of every non-DoT spell; Instead they're lumping all damage under the rubric of Wrath of Tarecgosa.

Everything you assumed is pretty much wrong. Check out this Wowpedia entry: Dragonwrath, Tarecgosa's Rest - Wowpedia - Your wiki guide to the World of Warcraft

I have a question concerning the current tier's 2pc set bonus and Living Bomb. Is there any information on whether you should recast Living Bomb with certain stacks? I am particularly interested in how this plays in with recasting on procs with the Will of Unbinding trinket, and similar procs such as the Insignia and Lightweave.

The general rule is to never refresh Living Bomb. Always wait until the current buff has fallen off and the explosion damage that accounts for one third of Living Bomb's total damage has been accounted for. The bonus damage from having intellect procs available doesn't make recasting it a dps gain over waiting until it falls of to refresh it. About the only time I will ever refresh Living Bomb on a target is when that target is going to be immune, untargetable or incapable of taking any damage other than dot ticks for a period of time. For example, it's helpful to refresh Living Bomb on the Drakes on Warmaster Blackhorn right before they fly away so that they continue to take damage from Living Bomb. Hagara and Alizabal are both bosses that take damage from dots, but are immune to all other damage for a period of time, so refreshing Living Bomb on these targets just before they are immune turns out to be a dps again, especially if there is nothing else to damage while the boss is immune.

In regards to the 2 set, having full stacks of it will not give you an additional tick on Living Bomb (or Pyroblast) so don't worry about matching Living Bomb with stacks. Having the trinket active will give Living Bomb an additional tick, however, one tick is not enough to merit refreshing Living Bomb. If you do have the ability to time intellect CD's with the initial use of Living Bomb for additional damage the damage gain will be greater than the benefit to other spells that do less damage per second. Refer to SimulationCraft for damage per second each individual spell.

In regards to Dragonwrath and ignite, I have never seen Dragonwrath duplicate ignite itself and I haven't read anywhere that it can. If you can find an example of Dragonwrath duplicating Ignite post it.

***
Edit by Heef - copied this here because it answers both the post that I've moved into this thread as well as one that I've left in the fire thread.

I'm having a few issues deciding when to cast my first Combustion.

My issue is with Stolen Time, by the time I get it to reach a decent amount of stacks all my spell power procs have dissapeared. On the other hand, if I use Combustion with all my procs (including Foul Gift of the Demonlord proc) I have a really long cooldown until my next Combustion and I don't have enough Stolen Time stacks to reach the extra tick on Combustion.

I feel like at the moment, I'm doing more dps when I use it with all my procs (but I don't know for sure). This might have just been to RNG granting me a nice ignite on those tries, or the fact that I'm using Foul Gift of the Demonlord (1 extra proc to align).

If I am doing more dps when I use my first Combustion with all my procs, do you think this will change when I replace Foul Gift with WoU?

Has a general consensus about when to use your first Combustion been reached? I couldn't find the information in the OP.

(Also, if it's important, my mage is a very new alt, and only 388 ilevel at the moment).