Replying to K2 Hellbent skis

Hey everybody what's good.

So after riding a bit with someone on Hellbents today in the park, my skepticism about a 127mm underfoot, rockered pow ski being good in the park was absoloutley blown away.
I definitely want to demo them before hand but there is one thing I'm curious about.
So I'm 5'9 150lbs. and ski on a 176 Ar6 now which I regret not getting in the 181.
I've read that the Hellbents ski much shorter due to the rocker but how much?
Would someone like me feel overwhelmed on a 189?  Im not like a pro skier obvi, I'm much better all mtn. than I am park (I'm meh at the park, can do a 7 w/o any grab, some ok 5's and so on but I am still working out my style). 
I'm not a spin to win guy so I'm not worried about the swing weight or anything but would the 189 feel wayyy to big even for spins 7 and under.  Also, how quick are these in the trees?  I hear the rocker makes it easy to pivot but I don't know so you guys gimme the low down.

Thanks