Replying to AR7, ARW, Stepups or Abangs?

Hey guys, I'm looking for a light and durable park ski that will be good for me to start hitting some rails amd kickers with. I'm an expert level skier who wants to make the transition to park from pow and off trail skiing. I live in New England and will prolly spend my winter on Mt. Snow. I'm 6'2' about 220 and im 20 years old. I want something that has good swing weight and is playful for like butters and things. I'm currently debating between the AR7 and the Line Stepups. to be hinest im leaning in the direction of the AR7. What i want to know is what length would be good for me and maybe some other suggestions that I havent thought of. I only need these skis for park because right now im riding Line Prophet 100's which are perfect for everything else. thanks guys