For those of you who are intrested in the unerring, i can tell you that om every fight where you run Divine star, unerring is absolute beast. I only have the normal version though, but i used it for our first ra-den kill this week. With the entire raid stacked with a proc up and you throw a star, you get a 180k+ DA on the entire raid =) I'm running 10 man and i'm using mastery reforges.
When it procs, i use my 90 tier talent (If i run halo or star, and ofc if its needed). If its on cd or not needed, i throw shields on people i know are going to take dmg, if there is no people taking dmg i usually penance/dot the boss for some extra dmg. If you hav enothing to damage or nothing to heal, renew is actually a viable filler when trinket is up, cause it snapshots your crit:P