Edit wood carver sigils?

[Bonder]

There is one sigil the wood carver gives most often, flying. I want to make it so this sigil cannot be given.

Anyone know how I would go about modifying the wood carver?

Changes like: removing sigils, changing drop chances for individual sigils or sigil tiers, when 1 or 2 totem heads are given, or when the amalgam is given.