I'm not sure how this particular modeling myth got started, but it's very clear the rows of swirls were never used on any Fokker aircraft. Sopwith used this technique and maybe also Aviatik on some aircraft. But never Fokker. I think part of the reason why we see this particular "error" over and over and over again, is that people just like the way it looks and don't really care if it's historically inaccurate. They just want to do it! And of course the fact that SR Batteries actually includes a tutorial on how to do it on their website propagates the myth. And you're right that a lot of (poor) museum replicas also bought into this myth.

To practice, I bought a cheap aluminum pot from the $1 shop. At first I tried to replica the exact squiggles I was seeing in original photos. But somehow it ended up looking more like Arabic writing! Then I thought about the poor factory worker who spent all day grinding away at cowls. He's not trying to create some pattern. So, my best result came from using 1-3second burst with an electric eraser and just working of fulling up the cowl with a certain density of squiggles. I think it looks pretty good...maybe not perfect but very close.