@L-i-am
Appreciated mate, thanks.
I know of developments when I was looking which included a simple arm on a low friction bar at the tope of the unit, sorry but I cannot find pictures, it was thirty years ago though. I did this for giggle and kicks, no doubt if I were seriuous about it I would look up knew (Pun intended) methods.
In short, you are correct. Keeping the orientation of the 'needle' will be difficuilt even in the example you posted.
Thanks mate, I appreciate you taking the time.