Affixing: How to get stigma to 70%?

Hello. I just have a quick question: I am doing 5 affixes and want stigma on my weapon. with three copies of stigma you get to 50% but yesterday I was able to get it to 70% and I have no idea how I did that. I searched the forum and nothing about this yet. I googled and it said I have to use ultimate quest boss souls to do it. Which boss souls?

Thanks in advance!

The boss Souls that boost Stigma are, by area:

  • Ultimare Naverius:
    • Beari Soul
    • Diabo Soul
    • Siogr Soul

  • Ultimate Lilipa:
    • Leone Soul
    • Granz Soul
    • Leopod Soul

  • Ultimate Amduskia:
    • Deadlion Soul
    • Deubarz Soul
    • Gryzorus Soul

Thanks so much!