RF build, what to socket into Doryani's?

I've mostly followed the build listed here: http://www.pathofexile.com/forum/view-thread/926461/page/1 (with the exception that i haven't got dual curse)

I do tons of damage with RF and love it... but for bosses like Atziri, what should I socket into Doryani's Catalyst:

1) damage boost: flameblast + spell echo + conc effect

2) damage boost: searing bond + inc burning damage + ?

If you needed more dps, you should use Conc/Echo/FlameSurge, if you are using Elemental Equilibrium, this might be not as efficient for you to be doing, just stick with cyclone/whatever to proc your EE.

I would personally just add a manual casted Enduring Cry, even with a CWDT setup
Or you could also put in vaal skills in there, skellies and grace are excellent options for you

arctic armour + elemental weakness + empower

Do you already have a primary skill in your chest?

Cwdt + cold snap + searing bond is what my rf currently uses in the catalyst with chest socketed incinerate.