In performing this movement, we recommend anchoring the elbow on the body, and driving the movement from the floor (note the heel lift), then through the hip, and moving the arms last- much like in striking or executing a Judo/ wrestling throw.
A priority with the mace (or any implement) for a progress-minded athlete should be using enough weight and ferocity to develop transferable power and dexterity.
Too heavy is sometimes just too heavy, but by the same token, too light is too light (and often even more limiting).