Derek Cohen (in Perth, Australia)
I spent today at a workshop on box making and veneering run by Andrew Crawford (who very modestly calls himself a "box decorator". His work is amazing. Link below).

At one point I noticed his steel rule. The reverse had sandpaper glued along its length. Here it is (on a blow up of a veneer he did) ..

I had to convert one of my steel rules as soon as I got home. Here it is with 240 grit on the rear.

Note to keep the edges free I bevelled the sandpaper with a sandpaper block (if that makes sense).

Verdict: Perfect nonslip. Marking will be so much easier in the future.

Regards from Perth

Derek