I did it at level 28 and honestly had a bit of a struggle. Balthier with Silence Shot in his gun helps IMMENSELY. I'd wait until after completing Mt. Bur-Omisace however, just do you can dispel his buffs. It was a hell of a lot harder with his defense up. I had Basch tanking it whilst Penelo and Balthier sniped it from a distance. Once I got it down to ~30% HP, I just blew it away with a quickening chain.