Here’s a couple of adjustments I’d add to try to get what you need:
This will make sure the adjustment goes down, as of right now you’re always getting a hit on the line trace so it’s never going reverse.
Also experiment with play vs play from start and reverse vs reverse from end. 
To add play into the needle you’re going to need to add a “Set timer by event”, and off of the “Completed” part of the timeline, run that, and every .2 seconds (looping) using the “Set Timer by event” , use “Random Float In range” to get a float between -5 and 5 degrees and have it add that to the relative rotation.
Hope that helps!