Replacing Mid-point slider for 'normal' sliders

Hello there Forum.
I’m trying to create a solution which allows me to slide a couple of points up and down a Spline.
Currently, I’m using ‘Point on Curve’ but this doesn’t give me the flexibility I need.
The ideal situation is to use a [normal] Number Slider (with a percentage value perhaps).
I’ve been mulling this for a while…but no joy )-:
Can someone please offer any suggestions?
Kind regards,
PointonCurveSlider1|690x482 (17.3 KB)

Use Evaluate Curve (Eval):

As easy as that :wink:
Thanks for your quick reply AndersDeleuran.