Rubber or nylon washers?

My cat shield is making creaking and popping noises. As suggested by other members, I plan to try rubber or nylon washers between contact points. Which is better in terms of vibration noise dampening- rubber or nylon? Durability?

 

Nylon or HDPE for durability

 

Any non metallic thing in between will work. I just used basic weather stripping.

 

Either should work, however when I added them it helped but did not eliminate the noise 100%.
My fix was to trace all the plate overlaps with a sharpie and then added a layer of rubber roofing membrane between the plates and where they contacted the frame.
You should be able to pick up some scrap rubber roofing from a local roofing company for next to nothing.

 

I used rubber washers at first and I had vibrations that I could both feel and hear. I took them out and mounted the plates up without any washers or anything in between and all that went away, been running it like that for almost 2 years.