Those diamond files are great. One caveat tho, he mentions long life, which is very true. During their initial usage ""break-in period", they are much rougher than rated, but quickly break down to their rated grit. So you may see some really high abrasion rates during the initial use, then much slower after a few minutes. The "after a few minutes" is the correct working mode. Many people have complained about them wearing out quickly due to not being aware of this.
They are also sold in some odd shapes, like credit cards, which you can cut up to get into tiny places, rounds, and tapered cylinders.