I have skied whistler all season with my bentchetlers, Im around 5'11 and only 150lbs. Like has been said before, they ski short and measure short for a 183. I really love the reverse sidecut (early taper) design. In deep pow you can create any turn shape you like with zero hooking.
Originally I mounted mine at -1cm from centre but found the tail so big that it got hung up on me a bit. I really love them at -2.5cm. Crazy but makes such a difference.
Big rockered skis you really want to detune the rockered section as you dont want to catch your tips in sketchy conditions as a fat ski will act like a giant fulcrum on your leg/knee/pelvis.
I have skied the 179 hellbent and the bentchetler is a much better all around ski that kills it in the deepest of days.
I also ski a 179 obsethed which is my favourite ski of all time, I do like soft skis but ep pros are too pow specific. Whistler gets a lot of wet elephant snot for snow and the ep would get too deflected. The bentchetlers still rule in these conditions.
I like to ski alot of trees and pillows, mini golf type terrain. Im not really one for super tight sketchy chutes and variable terrain.In those conditions I would want my seths or something stiffer, Once you get up to 120mm plus underfoot, there is not the same leverage (read grip) on icy exposed faces.
P.S: Im going to Niseko/Hirafu too and have a job lined up December to end of March. gonna be sick......