http://www.tosbase.com/tools/skill-simulator/build/rgpywu3t4v/ is my planned build after seeing a video of it. It looked very interesting. Main mobbing tactic is using pasives to gather mobs to one area then using circling and an aoe to get rid of them all.
Looks like the usual Auto Attack build, which isnt really specialized in AoE, but Cannoneer could make up for that. Altho as far as i know those builds are mostly played with Muskateer because Muskets have a faster attackspeed.
I would leave teardown on Level 1 and lower Pavise to max Rapid Fire and put more Points into Stone Shot