Spindle too heavy?

[johnsattuk]

Springs will change their 'pull' depending upon how far they are stretched whereas a counter weight over a pulley would be constant at any Z position. If the weight was dangled inside a tube, that would prevent it flapping about.

One of the snags with counter weights is their mass, OK when static but any accelerating movements increase the forces required to move the spindle which may be counter productive.

I use gas struts which are more or less constant force with low mass. Can be a bit tricky finding the correct one, but there are adjustable ones which you can use, you start out with too high a force and let fluid out to get what is required.