Replying to K2 ,Volkl for backcoutry in Alps?

Hi guys,
I need to buy a new backcountry skis.
I ski especially in european Alps.
I got the opprtunity to have great deals both with K2 or volkl.
I'm 147 lbs, 5.8 height.
My choice is between :
Seth Vicious 179 or 189
Maiden 179 or 189
Volkl Karma 184
Volkl Gotama 183
The snow is sometimes powder, but often it can happen to find hard pack on it as well.
And often there are a lot of trees, so maybe a long ski would be difficoult to handle (especially couse i 'm light weight)
Can u help me?
M.