Hey, I know this may be late but you can use this mod http://www.nexusmods.com/witcher3/mods/704/? Here are the variants of her necklace:
PaAdd("items\bodyparts\triss_items\necklace_01_wa__triss.w2ent")
PaAdd("items\bodyparts\triss_items\necklace_01_wa__trissx.w2ent")
PaAdd("items\bodyparts\triss_items\necklace_02_wa__triss.w2ent")