181 is fine for your size for a park ski. If you are using it in the park it will be centre mounted. I haven't skiied the 1080 Labs but I hear they are pretty good (slight upgrade in terms of beefiness from the normal 1080). The CR Lab has awesome graphics, don't like the Candide too much, although he is an amazing park skiier (one of the best in my view). You will find park skis have a low swing weight, especially centre mounted, spinning will not be a problem. 171 is probably easier if you are skiing 100% park but 181 will be better all mountain. 161 is insanely short don't even consider it at your size it will be garbage for anything but rails.