Replying to Chronic Length for Me?

Ok, so I haven't been on ski's for over 15 years. I switched to a board when I was 12 and decided I want to go back to skiing. I've narrowed down my choice to the Line Chronics but I keep getting conflicted answers on the length. I'm 5'11 and I'm 175lbs. Someone said I should ride the 178 version and someone else said I should ride the 171 version. Most recently another person said I should ride the 164 version. Being as none of the people ever rode the ski I'm turning to you guys to help me out. Any help will be greatly appreciated. Thanks everyone!