I never like Reflect in the game either, but I found a major use for it in this battle. Those orbs of darkness really pissed me off after about 5 tries, so I tried using Firaga first. But Reflega has alot of range, and will reflect more if he uses it a second time. It may even hurt Seph himself if he decides to run in and use a combo or something. What's funny is that it sometimes even wins the battle for me since I seem to spam it when he uses those orbs.

Well, I mostly used Elixirs for MP, but I'm sure any healing item is just fine.