Optimus 8r parts

I have an old Optimus 8R stove that I want to refurbish so I can safely use it again. I have fond memories of using this monster.
I am looking for two parts:
1- The rubber washer for the fuel tank cap
2- That square flame-tamer I saw in a video long ago.
Any advice on where to find the washer and will any rubber washer do or does it need a specific type?
Any idea of where to find that flame tamer?

I still have and use my Optimus 8R that I got in the 80s. It’s an old reliable that keeps on going. In contrast, I have had a MSR Whisperlight that died and a Coleman Multifuel that is ok but sputters alot.

You have bought packets of multisize rubber gaskets from Amazon and I pretty sure one of them would fit as a replacement for the tank cap. I am not sure what you are referring to as the “square flame-tamer.”

Here is the exact configuration of the Optimus I use that is being sold on EBay. Maybe get it as backout for parts for your Optimus, or vice versa: