Frenchy claims CBN forms readily when smoked, that's why he decarbs his hash first.
Actually Frenchy says you need to get rid of the co2 molecule. He decarbs the crystals to get rid of 70% of the co2 molecule attached to the thc-a molecules (everything with "-A" behind its name has this co2 molecule). because the co2 molecule is basicly "preserving" and locking the terpenes. Also it will cause a gas curtain that will block the terpenes from entering your bloodstream. Decarbing the thc-a will transform it into thc. the rest will go when smoking it.
So after decarbing you should have 30% thc-a and 70% thc.
As a result of the decarbing some cbn will form, which is an oxidant if i am correct, therefore your hash looks brown (And also old degraded buds looks brown, because degradation happens over time). The darker your hash the more terpenes are in there, the higher the quality.
You don't want cbn, but you dont want co2 either, so you have to balance it out.
I am not hashmaker myself but i have experimented with keef from my grinder. it is fun and you can learn from it. you can actually see the crystals changing color and become sticky.
I don't really use numbers. just how soft and sticky the hash feels in your hand. It also depends on the amount of keef you have vs how much time you need to spend hot pressing it.
You can see it, feel it, smell it, etc.....
Not really sure if this is even on topic anymore... lol.