I've been compiling a grit comparison chart for various sheets, stones, &tc. I've got responses from several sources including Monsanto, E-Z Lap, and several other sources. I just went to Norton's webiste and sent them an e-mail requesting technical specs on their "Sandwet" sandpapers.
In the product search page, under "Application", there is a selection for "Sharpening plane blades and chisels" among a list of others.
-Zz "Zz Yzx" rhymes with "physics"; or " Isaacs" if you prefer.
formatting link