Sorry, I don't know much about lvl 27 because I'm twinking at lower lvl ^^
What I know is use the helm mythic for PvP and armor like tarlok assault for mage (lvl 25/26, forgot the item level)
tarlok maybe only in some lvl, in pvp 20-23 many people still use tarlok (lvl 20) for their equipment because high damage and nice stats.
Do not forget that gems is very important to improve your equipment for best stats, so I suggest to use gem for each equipment you will use

Pet for mage PvP:
Hammerjaw
Colton
Slag
Orion
Ribbit
Crawly

Maybe helpful..