I was personally in the same situation, with 1 water mage, 1 earth hybrid (first char... old school) and a wind mage. Eventually if you make a wind, do it ATK/Killer type, it's crazy how fast they are and they can do such a big damage... If you want it to be sealer, then add on MATK. I have 3 fires more now, 2 Attack builds and one mage... I love the mage more :)
As an answer to your question, I suggest to build a fire, then later a wind :)