I am in chapter 10, after (SPOILER)beating Cid, and I am using an all-girl party: Lightning, Fang, and Vanille. I like having two saboteurs for throwing a bunch of debuffs on quickly. I suppose when I need a synergist I can either swap in Hope or Sazh, or use a -sol before the battle. I may experiment with Snow vs Fang for the better Sentinel (and I like using Lightning as my COM instead of Fang, so Snow could be the second RAV).