Guild Wars 2

hi guys, i would like to know your insights regarding backstab thief
1. what do i use on armors? – what Runes or what Stones (ex. Ruby) what
2. what do i use on weapons? – what Sigil or Stones
3. what accessories will i use?
4. if i use sigil on ex. 2 daggers, can the SAME type of Sigil stack? or it must be of different type? and what if i swap weapons without sigil, can the effects of sigil from the prev weapon/weapons still stack?

thanks for all those who will reply.

https://forum-en.gw2archive.eu/forum/professions/thief/Building-a-better-D-D-thief/first