Replying to Another length question thread!

I'm getting some AR6s and some K2 Seths (broke both my pairs last year) in January but am trying to decide between the 166 and 171 in the AR6... I will mount them centre but use them in bumps as well as park..I'm 5'8 and about 125 pounds so pretty skinny.. Which do you think? I'm tending to the 166 because they look better.. With the Seths i'm choosing between 169 (mid forehead as k2 come up long) and the 179... these will be my everyday backcountry ski but also will occasionally see some piste skiing..