That is interesting, have to remember that.
To avoid having to insulate the bar, I made mine by screwing a piece of narrow aluminum bar to the edge of a straight oak 1 x 2, with the screw nearest the blades long enough to protrude above the 1 x 2. The protrusion gives you a metal surface to connect the ohm meter, or in my case, an automotive continuity light, to the aluminum bar.I don't think that the article specified what type of tape to use, but I believe that I'd try electrical tape - it's thin, and an insulator, which is what you're looking for.
That's exactly the way I have done it for years tom.I’ll have to try that. My current method is to lay a hardwood block on the out feed table and adjust it until the knives just touch it enough I can feel it.