Grumpy_Mike:
I am not sure what you think that video is showing but it is not showing a reading of how far along the strip the hand is but how far above the strip the hand or grounding point is. So it is not related to your proposed project at all.
1:10 in the video. “As I touch the pad, the LEDs light up. As I move my finger to the right they progressively light more and more”
I hope you can at least see where my confusion arose given the above!