I was just reading and printing out a 58 page Bassdozer article on plugology, he stated exactly what you did regarding needles, need to be tuned to the verge of being unstable....he suggested bending the eye up or down to accomplish this depending on the situation, good stuff....the needles that I've purchased seem to be weighted throughout ..in one case one in front of the eye, one behind and one about 2/3rds back ona 7" lure...trying to spread the weight throughout the body, I'm interested to see what the result would be from rigging one up and finding the point where the CG and CB line up as a result of placing a weight right there....interesting to see how the ends would act...guess I'll get on it starting tomorrow....btw..I was looking at a pencil
popper that I have and it is weighted with a single weight(I don't think there's a tail weight) about 2/3rds back and given the body shape this is probably near the point we're discussing and the first time I fished I couldn't believe how wildly it splashed back and forth with almost no effort from me...