I much prefer all the Evercoat products, very good fillers!!!! Most any auto parts store that has paint products should sell them.... They make one with some very fine strand fiberglass in it that is very, very strong. Think I'd use a small amount of it as a base, not much cuz it is quite tough to sand, then the Lightweight filler (they have about 5 different products, different prices) to final fill. Sands easy, doesn't clog up the paper and minimal shrinkage....