Guild Wars 2

Say that I have 3 weapons, a two-handed weapon in 1 set, and two one-handed weapons in another set. Say I put the superior sigil of bloodlust on my two-handed weapon, and the superior sigil of corruption on one of the one-handed weapons and the superior sigil of perception on the other one-handed weapon.

When I kill something with set 1, which stack(s) do I gain?
When I kill something with set 2, which stack(s) do I gain?
When I’m using set 1, which sigil(s)’ benefits do I get?
When I’m using set 2, which sigil(s)’ benefits do I get?

You only ever get one stack from sigils. If you start stacking bloodlust you won’t stack any corruption or perception until the bloodlust stack disappears. When you have two stacking sigils on one hand weapons it picks one and only stacks that. Not sure which it picks or if it’s always the same since I never use two different ones. If you have two of the same stacking sigil in one hand weapons you will stack them up twice as fast.