I use crucible most of the time. If anyone in the grp is running focusing iris i sometimes use the one that can copy others essences. But its a bit of a hassle because of the channeling needed i think.
For minors i always run ever rising tide and then play around with the others depending a bit on the affixes. Tyrannical weeks i usually go for the one that gives mana back (lucid dreams?). And i usually use the one that boosts my healing surge. Yeah i suck at remembering the essence names 
u have conflict rank 3 so u should probably use that as a minor always.