im saving up for new twins this summer but im not sure what length to buy. ive been skiing on 163's for the last two seasons and im used to them, but im going to park city next year so i need longer skis in order to go fast enough to clear the big tables. im 5 foot 11 and weigh 155 and the bindings would be centered so help me out should i get 169, 175, or 179?? i heard that longer skis are harder to spin on.