Replying to Ski Length Help

Hey NS, I'm just about to pick up a pair of new Rossignol Scratches, and just wanted to get a few other opinions on the length. I'm 5'8, 140 lbs, and 16 years old. It's between either the 167s or 174s, but as of now I'm leaning more towards the 174s. I've been skiing since I was 8, but this is my very first pair of park skis, and the first year I plan on giving the park a try. I want to do a good mixture of jumps and rails. Let me know what you think.