The Magician is meant to be identical to the Mage - Magician's Versatility was accidentally omitted from the text in CoM when the book was enhanced. The intention is that future products will include additional spells marked for use by the Magician/Mage and that there will be more than enough of these to more than fill the missing Magician sphere slots. If you cannot wait, you can allow Magician PCs to take spells from Elementalist, Necromancer, Thaumaturge or Vivamancer Great Circles at GM discretion.
Best wishes,
Nicholas