Replying to 161 or 171 Invader?

About me:  This ski will be used for just park.  I am getting this ski for just the rest of this year, because my binding heel piece ripped out today, for the second time this year.  My core is done on my other skis and they've been drilled too much at this point.  I was planning on getting Afterbangs next year, so I had this money set aside.  I am 5'4" in height and about 125 pounds.  Again, this will be just for park.  My park has no jump bigger than 20 feet.  So here's the question.  171 or 161?  I will be pairing this ski up with a Look PX12 Jib binding.  I only plan on using them for the rest of this season.  I am leaning towards 161since it will probably be easier to throw around.  Will a 171 be much harder to throw around than a 161?  Please let me know if I'm forgeting any info.  Thanks for the help, much appreciation.