Fly tying is a mixed up mess without any useful standards and thread is a classic example!

0 rating - x/0 thread is whatever a particular manufacturer chooses to call x/0. (correct me if I'm wrong here) This is useful for comparing threads of the same type from a particular manufacturer but little else.

denier - gram weight of 9000 meters of material. Is that metric grams? This is useful for comparing threads of the same material but isn't comparing the denier of two different threads like nylon with polyester essentially comparing apples to oranges?

Why can't we have useful standards? Chris Helm's chart lists breaking strength and diameter for fly tying threads! If thread manufacturers listed their thread by breaking strength and diameter (like fishing line manufacturers do) we would have some useful information that would allow us to actually compare different fly tying threads. I will not live to see the day.