I am about your size, have a deep maritime snowpack, lots of trees and also fast open spaces. I find the 182 to be fine, possibly a bit much for me at times due to constant tired touring legs and because I am not a great skier, and even with a pack, I am a lightweight.
The 192 seems an all round much bigger ski than the 182, almost a different model. After skiing the 182 quite a bit, I reckon I could almost monoboard my skinny frame on a single 192.
I posted this before, Sage saying that the 192 is a bit big for him
http://www.backcountry.com/atomic-atlas-ski-ato0323
The Atlas seems to have fallen through a hole and for what ever reason not many people talk about them. Seems odd. It strikes me as a very legit ski for solid skiers.