Need help with an RF caster build

I'm trying to determine wether i should go for an Elementalist or a Chieftain when making a Righteous Fire caster build.

Do anyone have any tips/suggesions?

Skill Trees

Chieftain: www.poeurl.com/3E9
Elementalist: www.poeurl.com/3E7

These are the uniques i'll be using:

Doon Cuebiyari
Repentance
Astramentis(or high int amulet)
Rise of the Phoenix
Lioneye's Vision

The spell i have chosen to use is Arctic Breath, wich i'll be fully converting to fire through the use of the Cold to Fire support and Avatar of Fire keystone.

Hopefully someone can help me :)

Edit: Went for Fireball instead and swapping out GMP for slower proj on bosses. Currently lvl 46 on an Elementalist.

Chris