How obvious is spellcasting

How obvious is spell casting and supernatural abilities.

For example, someone is talking with a person and has eye contact. How obvious that they do a silent/no gesture spell?

What is the difficulty to notice a hex or entrancement being used?

Someone is talking with people or practicing weaponwork in the yard, someone goes to cast a sight range spell on them, how easy is would the awareness roll to detect it being cast?

On that note, how noticable is a sigil? Does it go as casting is complete or during casting?

I'd say that would be extremely hard to notice. Perhaps a sigil would be noticed, but what else is there to notice except the spell itself. And if the spell has no visible effect, what then?

I would say that might be a Folk Ken roll based on familiarity with the person affected and based on how out of character the person is acting. Even then, you would just know something is up, but not what.

From Sight range far away as opposed to closer using Sight range? The sound won't carry that far in any noticeable way. That would be visual perception, but they're distracted and the actions to be observed are small and very far away. Seems ridiculously hard to me, except for perhaps the sigil or the spell's visual effects.

I think that entirely depends on the sigil, those observing the sigil, and the environment. I would say a lot of sigils I've seen would go with the completion of casting because they're part of the spell. But you could have a sigil that your eyes glow as you cast. I would read through the examples on page 86. I would say a sigil that goes with the spell comes into being with the spell while one that affects the caster probably happens during casting (the caster's part of the spell); ones affect the environment could go either way depending on what they are, but I would generally guess on completion of the spell.