Your story triggered my "Vega memory" when I first ran into the composite float in the carb, which over time absorbed fuel, got very heavy and much less buoyant, and finally didn't float much at all. Similar performance issues, and when I finally figured out that it was flooding out the bowl to the point of over flow on corners I bought a new float and was amazed two fold. First, the old float weighed about three times the weight of the new; and two, the car ran amazing because everything on it was checked, double checked and adjusted to spec by then from chasing the problem. Moral, don't trust that the solid composite float is OK. They're cheap, and they fail slowly over time.