And consider picking up the Theoretical Magician trait (+2 trait bonus to Spellcraft checks) while you are at it, if you are trying to boost you Spellcraft bonus as high as possible.
Be a Spirit Guide oracle. At 3rd level you can choose Ancestors or Lore spirit, they have a hex that gives Wis to all int-based skills. But as a Spirit Guide you swap Wis and Cha. Therefore, Cha to spellcraft.