The amount of quilting, and whether it's machine or hand quilting would not greatly affect the weight of a quilt, but it does change the density, so a heavily quilted quilt will feel heavier for its size. The quilting flattens the layers, forcing out the air, so the quilt takes up less space and is less buoyant. Tying a quilt instead of machine quilting it will make it seem lighter and easier to handle because it is less dense and incorporates more air. Does this make sense to anyone else?