I got my black ark from Dan's and it was flat. I used the 300/1000 to do the preliminary burnishing. I was told by Don at SRD the Trent can be used to lap the black ark but I didn't need to do it. I don't know how it will work if the stone needs some serious flattening. It is well worth the extra money you pay for a Dan's to get it flattened. Even with the Trent, I had to do about 200 laps with an old razor to really burnish the stone. I will say however it is smooth as glass and really does make a difference on finishing a razor. Just takes a lot more time then my Escher or Jnat. I also found WD-40 works wonders on the stone when honing.