I also use the Cerberus fight to stock up on Triples, because it can be an easy fight if you're well-junctioned and Dispel his own Triple when he casts it. I already have several full stocks of Quake (T-Rexaurs in the Balamb Training Center) by the time I get there, though. Quake, and then Tornado when I get it, are my main STR-J magic on the first disk.