Not sure how the Don says to use the scraper, but the way that I was shown in an engineering workshop made it look rather a difficult tool to use. I was told that the main use for the tool was to remove a few thou at a time to true surfaces. For the most part knife making isn't that much of an exact science, or so it seems. So far I have found that fine wet and dry and a really flat surface works for most surface truing.
I will be watching this space with interest. Hope someone with more experience shows up with a better answer.
Chris