Masterwork!

[Shhalahr Windrider]

Yup, that makes sense, though it leaves the Perform (oratory) and Perform (song) types in the lurch somewhat.

As I pointed out, not every skill necessarily has a special tool to provide a bonus.

You copy a piece of paper onto the vellum. Then you stick the vellum over the right kind of paper, and flip it up, to compare your work on the opaque paper to a reference copy.

Figured there was something I was missing.