Not sure on a full build just yet, but Kneeling Shot and Running Shot look pretty solid, as well as all the crit chance bonuses for Kneeling, Swift Step and Sneak Hit. Filling out at Rank 7 with either Cannoneer for more AoE or Musketeer to really wreck bosses.
Unsure if this is wise, never touched Quarrel Shooter yet and don’t even know what to max outside of Rapid Fire and Running Shot. Any suggestions?