Get thumbs from both hands in same position in Unity

[Anonymous]

Dear forum,

I am trying to bring both of my character's hands into the same gesture in Unity (using a C# script at runtime). For all four fingers except for the thumb, it's easy: the same rotations lead to the same gesture. For the thumbs, however, the same rotations lead to very different thumb postures, and I have not found a way to translate the left thumb's rotations into according right thumb's rotations (there does not seem to be a linear offset that robustly corrects rotations in various gestures). The attached Image shows both hands with identical bone rotations.

Does anyone know how to translate thumb rotations from one hand to the other?

Thanks,

Marius