I'm getting some success with the following (i.e. higher dps than my arcane mage)

Button 1 has:
Code:
/petattack
/stopmacro [channeling]
/castsequence reset=target curse of the elements,null
/castsequence  reset=target/5 Immolate,incinerate,incinerate,fel flame,incinerate, incinerate,incinerate
/cast Chaos Bolt
/use 13
/use 14
Button 2 has conflagrate, button 3 has shadowburn and button 4 has dark soul-instability

I use grimoire of sacrifice (suggesting /petattack becomes useless).

All 4 buttons get mashed at the same time.