My favorite party was Crono, Lucca, and Magus. Their single techs (Flare, Dark Matter, Lumina) end up doing more damage than double/triple techs would, since they take the turns of two/three characters and don't do as much as even 3 luminas, which in my experience, has the lowest damage output of the three ultimate techs. Since none of the enemies in the game have a whole lot of HP aside from the right lavos bit, healing seems to take a backseat to damage done. Besides, there's always lapises and megalixers.