Guild Wars 2

What happens when you wear 2 weapons with same sigil? I know for some but not for all… here are the ones I know (with example):

Permanent stat bonuses – No stacking, so it’s better to use 2 different ones (example: 2 sigil of accuracy give 5% crit chance still but 1 accuracy and 1 force give 5% damage and 5% crit chance )

On-kill stacking effects – The stack grows faster (2 instead of 1 per kill… 10 instead of 5 in PvP) but the limit is kept the same (25)

Condition duration bonuses – ? (really interested in this one)

Bonus damage versus specific foe – ?

On-kill one-time bonuses – ?

On-kill charging effects – ?

On-critical-hit – ? (also really interested)

On weapon swap – ?

PS.: sorry if wrong section to post or if topic already made but I haven’t found it.