Are you boosting Magic? I took Penelo specifically to Multibreak and increase Magic.
Edit: In fact, you should be running two mages, your best healer, Multi/Magic dance (Tyro or Penelo), and your Pecil should be Draw Fire with Steiner's RM. You should be able to pop off two to three BSBs and use his AoE (Defend command) to scoop up stragglers just as Ashe RW is running out.