Kirby E. did Jim's end-pour idea in both ends of his Ninja when he was looking for a symmetrical lower float. He was saying that it made a tangible difference in the feeling of stabilizing inertia having the weight energy out at the ends.
Ill see if I can get him to pop in and comment on that.
Here in the dirty south a sawed off dumbell weight end placed in a hollowed out place in the foot block is a popular option. Talk to the right person and they will tell you where they keep theirs stashed on the bank at park and play spots.
