So this is basically just like the one before just we are going to use the arc length of the spline along the joints to give a better and more reliable scaleing of the joints. Select the curve, now type the next mel script, arclen -ch true (name of the spline or curve); this will create or make accessable the curve info node that will allow you to use the arc length rather than using the measure tools, this will make it much simplier and less complicated. now create the multiply divide node, plug the arc length from the curve info node into input 1x and put the same number into input 2x. change the multiply divide node from multiply to divide and connect the output to the scale x of all the joints. now when you move the controler it will scale the ik spline correctly. this is better than previously because with the measure tools if you moved them in some positions, it didnt calculate the scale correctly and would look funky.
enjoy : D