I think that the current behavior of the sliders should be modified.
Currently, when you click to move the slider, the slider jumps the the location of the mouse pointer. This can be problematic. It's possible to instantly change you spindle rpm to 50% or less during a heavy cut if you are not careful when manipulating the slider. This can be dangerous, and result in broken tools.
The proper behavior should be that the slider position should not change when the mouse button is clicked. The slider should move proportionally to the mouse movements, but not necessarily move to the exact mouse position.
If the slider is in the middle, and you click on the left edge and slide to the right, the slider should start where it was, and move to the right from there.