Arghhhh...this new software is driving me crazy! I just lost a reply due to a timeout I think. Am I missing something?
Anyway, the diamond triangles (they aren't sleeves, but hollow triangular tubes) work great. As Sal said, they remove metal. In fact, my first use resulted in some un-even grinds because I put too much pressure on the edge. Patience is called for when using them.
Are they worth the cost? Based on pure performance, definitely. Will they hold up long enough to justify the cost? I've only used them on about a dozen knives, so it's too early to tell. I know production was held up while they worked on the adhesion, so I'm optimistic. Consider that before taking my advice - if you have a 204 and need something to handle serrated and/or recurved blades, you won't be disappointed.
I had a good set of Razor Edge System's benchstones prior to buying the diamond triangles, and I plan to continue to use them whenever I can. I'll reserve the diamond triangles for my recurved, serrated, or other oddly-shaped blades. No sense in wasting them.
What we really need is someone to buy a pair and then proceed to attempt to wear them out...