Replying to Right length for powder skis?

So I'm currently skiing some volkl karma's in 177 and I'm thinking about picking up a pair of powder skis for this season.  Early season will probably be spent on the east coast but I'm planning to make it out west for two weeks or so.  Right now I'm looking hard at the k2 ak enemy's, the volkl gotama's and the maybe the liberty helix's.  Ive seen a few ak enemy's in 189 length but I'm wondering if that is gonna be too long for me since I'm only about 5'11 or so.  Any advice would be helpful, I'd post over at TGR but they don't take kindly to noobs like myself.