Well, common sense is a good guide. A small elite of pikemen and african swordsmen, light and heavy liby-punic phalanxes, thureophoroi and thorakitai style units, javelinmen, archers/slingers, 1/4 (of total cav force) light cav, 2/4 medium, 1/4 elite. Numbers vary depending on your fighting style. I find that the center of my line rarely gets hit hard so I use less phalanx units and more light and maneuverable ones better suited for the fighting that occurs on the flanks of my force. I also use light and medium cav better than heavy cav. I guess this only shows that Carthaginian armies can be very flexible and promote a more fluid fighting style.