THM in <35 dungeons (low level) advice?

[Malevicton]

You should absolutely use Sleep at low levels depending on party composition and dungeon. Look at your other DPS. Is it a melee? He probably doesn't have area of effect (AoE) enough to be worthwhile. Is he a Dragoon? Dragoons don't have AoE damage early on. Do the mobs hit hard (Brayflox dungeon)? Yeah, go ahead and sleep the extras. Do you have a Warrior tank? Wait until he stops using Overpower to sleep things. Is your tank taking too much damage (undergeared, lower leveled)? Sleep.

Do you have a Summoner with you? They'll put damage over time effects on all the targets. In that case you might as well AoE all the targets alongside him. Is your tank pulling absolutely everything around? Go ahead and AoE. Do the targets have little health and would die quickly? AoE.

even if the other dps doesn't have good aoe, he'll always have fire2. And no one really expects sleep anymore, so it's probably just gonna get broken. Sleep can be helpful if the group is playing around you using it, but no one really does. Fire2 all the way.

[Warlyx]

Fire II all the things!!!! but bosses :P , THM are the best for dungeons at low lvls , infinite mp , good aoe and good single target dmg :3 , just be aware of agro , let the tank flash / overpower at least twice before unleashing hell

U wont be using sleep , its usefull if something is hitting the healer and tank doesnt notice it ....and even then....meh...

[Rongway]

When using Thunder on trash, don't cast it on target #1. Cast it on target #2; target #1 will most likely die before Thunder ticks for its full damage. (Let the tank hit #2 or use Flash/Unleash/Overpower before you finish casting)

Besides that, the rotation without Fire III is

Spam Fire until out of MP
Transpose
Blizzard
Thunder or Blizzard
Blizzard (Not Fire!)
Blizzard (Still not Fire yet!)
Transpose

Repeat.

Breaking Umbral Ice with Fire I will result in two unbuffed fire spells (one to cancel Umbral Ice, and one to gain Astral Fire again). As it happens, the cooldown on Transpose is such that you can cast two more Blizzard spells instead before Transpose is up, and you won't risk shorting your MP refresh by breaking Umbral Ice early. Blizzard will do the same amount of damage as unbuffed Fire.

If the other DD is a non caster, switch to #2 when #1 only has enough health left to survive one or two hits. If you don't, you'll get interrupted because the other DD killed your target.

[Twilite]

When using Thunder on trash, don't cast it on target #1. Cast it on target #2; target #1 will most likely die before Thunder ticks for its full damage. (Let the tank hit #2 or use Flash/Unleash/Overpower before you finish casting)

Besides that, the rotation without Fire III is

Spam Fire until out of MP
Transpose
Blizzard
Thunder or Blizzard
Blizzard (Not Fire!)
Blizzard (Still not Fire yet!)
Transpose

Uhm.. you should only have to cast Blizzard twice after transposing, if not using thunder.

[Rongway]

Uhm.. you should only have to cast Blizzard twice after transposing, if not using thunder.

Breaking Umbral Ice with Fire I will result in two unbuffed fire spells (one to cancel Umbral Ice, and one to gain Astral Fire again). As it happens, the cooldown on Transpose is such that you can cast two more Blizzard spells instead before Transpose is up, and you won't risk shorting your MP refresh by breaking Umbral Ice early. Blizzard will do the same amount of damage as unbuffed Fire.

Quote context.