Bill Tindall, E.Tn.
What was the range of sandpaper available in 1995?

same as today. Same as when machinists refined metal surfaces to a high polish decades ago. Same as when I polished metal on set ups for metallurgy microscopy in the 1960's. Graded abrasived have been around for centuries.

This revolutionary sharpening procedure was simply metal polishing of a bevel. A call to any abrasive company tech service would have gotten an informed recommendation. I happened to call Klingspor, but 3M or Norton, etc would have gotten the same result.

The substantial advantage of sheet abrasive is the opportunity to proceed with small steps in particle size so that only a few strokes are necessary on each grit size. Much faster than using 2-3 stones of widely spaced particle size.