We also stopped dps at about 32% to avoid getting Subetei out on a flanking and further complicating things with a Volley. Once we were allstacked again after the 2nd Flanking we'd pop personal CD's and easily get Qiang down before the 3rd flanking/pinning arrows.
Basically this. Stop DPS at said percentage. Wait for the Flanking Order, reposition, hit bloodlust and kill Qiang. This alones makes the transition much smoother.