I have been running the same setup for about 2 months without a notch in the pin,

I dont even bother with the screw that holds the pin in.
Here i just made sure the pin rotates freely in the arm, so the set screw is always holding it in the hub tight. i just check them after every meeting, but have not come loose just yet.

I used a 2.5mm drill bit and a 3mm set screw to get lots of thread bite on the screw.

Beth.