The Surly lockring mignt be good to try if there's a problem with getting enough thread to tighten it up properly. It has a little raised lip that goes in under the cog and results in more lr threads grabbing. (see pic)

But I wouldn't let one forum thread with some vague hearsay type stuff cause me too much stress over a $15 cog, especially since other posters in this thread have had no problem. Maybe give it a try and report back.