I'm a bit unclear about a couple of things regarding souls and enchanting.
I've gleaned that human souls are 'black souls', while all the creatures have 'white' souls. But I just killed two soul-trapped bandits (including one bandit chief) and now the only two black soul gems I have have grand souls in them? The wiki says bandits have grand souls, but also says that all NPCs have black souls. Does it mean only named NPCs have black souls?
How exactly does the level of soul affect enchantment strength in weapons? In apparel I see that the effect varies, but with weapons it only seems to affect how fully charged the enchanted weapon is? It also doesn't seem to make much difference (like, 10%) between, say, grand and petty souls. Am I missing something?
In general, what is the way to go for enchantments? More charges, more power, or somewhere in between?