Guess, i'm going into accuracy, power and crit...

Hi all! I'm pretty new to SWTOR and playing for sith assassin in deception. Right now im 44 lvl and got 840 common data crystals. Considering that 1000 is the cap, i'm going to buy some "Outlander" gears for common data crystals and use it on 65. What stats (pummeler, proficient, etc) should i buy? Or should i spend the crystal on omething else (like what)?