They will ski fine at true center, but looking at whatever years model of Future Spin is on the website, they are not a symmetrical ski. Line recommends -4 because that is where the ski will perform best.
bitches love it when they can see my dick bulging against my outerwear. they are all like "is that a sandwhich for later?" and im all like "no, that is my massive penis sandwiched between the tight fabric of my pants and my inner thigh" - pomme-de-terre