hey megtab,
i'm from western canada as well (bc)!!!
again, i'm not familiar with the powder version of the exclusive but got a chance to ski on the women's version of the legend pro model.
my specs: 5'7" 145lbs 23 yr old fairly aggressive skier
the length i skied was a 178 and dimentions of the ski were around124/97/116 (i'm guessing a bit here, as i can't remember the exact digits!) . . . and unfortunatly i can't find the exact ski i demoed on anywhere . . .
but they were an amazing ski!
stable, fat, fun, and turn on a dime, yet are stable and carve as well. they were the ultimate all around ski.
my one and only complaint was that they were heavy . . . really heavy, and demanding (these skis weren't very forgiving).
BUT . . .
from what i've been told and from my own investigating, the legend series have VERY similar charicteristics . . . they're all amazing skis!
the differences are more in the stiffness and weight.
the exlusive powder version is supposed to be a bit softer and lighter than the pro version, so it sounds like it would be great for you if you're looking for something aggressive/responsive, but with a bit more forgiveness.
dynastar deffinately blew me away . . . legends are VERY NICE skis.
also, in regards to length, i'd probably go longer than shorter taking into consideration your skiing style and the fact that you're generally skiing deeper snow out west

!!
i enjoyed skiing the burly 178's and LOVED them in the trees -- even when the trees got really tight (the legends manuvered VERY well for such a big ski).
i know i rambled a lot, but i hope it helps . . .
demo if you can!
cheers,
lil mtn girl