Board Thread:General Discussion/@comment-24583358-20140803004541/@comment-1883569-20140803065249

No, you can only get 161K  experience in total, so no 161K for fighter and 161K for mage. Because you want to have an arcane warrior with lvl 5 spells, you must dual-class when reaching fighter lvl 5 (16K xp) in order to reach mage lvl 9 (135K xp).

Also, when creating a character to become a dual-class fighter/mage, it must have 15 Strength, requirement for dual-classing with fighter and in this example 17 Intelligence requirement for the mage. In the case of picking a class kit for the mage (don't if this is possible), see Specialist Mage, as this adds another requirement.

You can dual-class as early as reaching lvl 2, in the case you can't pick a mage, you have done something wrong.