I hear all the time that red coral earrings are the best earrings for a Disciple of the Hand, but they provide less CP than Crimson Standard earrings. Even if you meld a craftsman's cunning materia IV into the red coral earrings, you're tying with the Crimson Standard earrings for CP, and the latter still wins out due to increased spiritbond rate.
I could be wrong, but it seems to me the only way the red coral earrings are better is craftsman's command materia IV being melded into them. We have enough craftsmanship on everything else, don't we?