When boning a long tail or neck it seems intuitive to match the bone joint to the spline ring.
However, you'll probably get a more natural deformation if the spline ring is in the middle of the bone.
PRJ you can play with... TailTest01.prj
The top is spline-ring-at-the-joint. The bottom is spline-ring-at-the-middle...
Tail Bones800.mp4