Fire/Poison Mage Builds Post-Big Bang?

I'll expand on this post later but here's a quick sketch of a build I came up with. Won't be using it myself since I'm already 15x, but I think it's the best way to build an F/P.

1st job
1 Bolt
Max Magic Claw
Max Magic Armor
Max Magic Guard

2nd job
1 Teleport
1 Fire Arrow
Max Mastery
Max Fire Arrow
Max Teleport
3 MP Eater
Max Meditation
Max MP Eater
Max Slow
1 Poison Breath

3rd job
1 Teleport Mastery
1 Explosion
3 Elemental Amplification
6 Booster
Max Elemental Amplification
Max Poison Mist
Max Teleport Mastery
Max Explosion
Max Elemental Composition
Max Elemental Reset
Max Partial Resistance
11 Seal

4th job

1 Paralyze, 1 Meteor, 1 Big Bang
Max Buff Mastery
Max Paralyze
Max Big Bang
Max Infinity
anything but Mana Reflection

I don't see the point in dual channeling, changing channels takes longer than waiting a couple seconds for more mobs to spawn.

While I was looking at it, I opted for Mist before Amplification since Amplification doesn't affect Mist's damage over time, and I felt like a Mister wouldn't rely on any DPS to train, though that does raise the question of why I maxed Teleport Mastery first... Mine could definitely use a few tweaks there for optimization.
There was an odd glitch where Elemental Composition was not affected by Elemental Decrease. This is likely unintended, due to the mechanics of Elemental Composition being half Fire and half Poison.

Dual channeling is for really small maps where you do take a lot longer to kill monsters if you're weaker. It'd likely not be viable though since characters shouldn't be that weak to begin with.