just bought the new 06 fujative's and got the 159... but i have the option of switching out sizes if i want. im 5'4" 110-115lbs. the 159's come upto the middle of my forehead and the 169's are a tad longer than flush with the tip of my head... what should i do?? is there any rule to sizing with twin tips...like the rule snowboarding has of the board coming upto your nose...hmmmm??