How did you find your ancient Hexing Pants?
Blood shards? Loot? Upgrades? Rolling on another character?
Drops are best, but upgrading rares is a good option as well if you are desperate.
I would say drops and shards at first. upgrading rares from the yellow kadala gives you can also be an option. And if you have really bad luck and everything else is ancient perfect, you can always turn to the cube reroll option.