Anyone know whether these would hold up on the trail? I'm looking at some rain pants by Rain Shield - http://shop.rainshield.com/products/productdetail/part_number=1060/4889.0.1.1 - according to a company spokesperson, Adam Ziskin, "They weigh about 4oz. They are made of a non-woven polypropylene laminated to a polypropylene microporous film." Thanks. Nikii