As of now it seems to me that the minimum requirements are 3 unhold hides and 3 piles of shimmering ashes from necrosavants. Additionally if you come to the location having unhold hides and/or ashes in the number required to finish the "quest", the number required will go up by one, let's say you have 5 unhold hides in the inventory, the witch will ask you to fetch 6 hides, If you have 9 piles of vampire ashes then you will be required to get 10. That is too much, not only you are forced to waste a lot of inventory space but also waste a taxidermist ingredients, lastly ashes are hard to get as there aren't that many necrosavants locations, especially if the undead scoruge didn't happen. I suppose the limit is always (min. 3, if more than 2 in inventory then x in the inventory + 1), and it's there to prevent the player from triggering the event 3 times in quick succesion for whatever reason. Regardless I would like to know why ther is no cap on that.

Attached: Witch asks me to bring 10 piles of ashes after I wiped them of the face off the map.