Ok having read the "vibe" of this thread so far, I have a question as to direction of placement.....
In a crankbait, or any bait that relies on wobble/wiggle for action, I would tend to agree, side to side placement is optimal. But with a jerkbait, which is what the OP was posting about, the action is more of a "jerk" toward the line, and not so much a wobble. Would that not make the optimum placement for the rattle to be parallel with the backbone, ie in a nose-tail orientation?