I'd lean more towards Gallia. SW databank says that she is skillful fighter and the Force is strong with her. With the Force, she easily ripped a large boulder off the ground and effectively pwned Aurra Sing with it. Kenobi hasn't demonstrated anything particularly as impressive.
The fact she is also a master of an unorthodox form (reverse grip, like Starkiller), gives her an advantage insomuch that Obi-Wan likely hasn't encountered anything like it before. As well, I don't see AOTC being able to cut through two MagnaGuards with casual ease like Gallia does in Obsession.
Added with her position on the Council and experience, she wins.