You seem to have a good understanding of the Kukri dynamics, At 18 inch and 31 ounce, it probably doesn't perform far from what a 25 ounce would for the same length. It is only 25% or 6 ounce heavier. The extra weight is spread across the whole M43. To me (and my very humble opinion) it's the length that makes the biggest difference. A 18 inch 30 ounce feels much heavier in the hand than a 16 inch of the same weight. These guys are nose heavy and the lever works against your wrist.