SecondaryNormaMapWeight

[Consort]

I understand that the SetSecondaryNormalMapWeight functions control the normalmap (or bumpmap) for the muscle definition of a sim.
But why does it not just take a value but also an index?

Are index 0 and 1 describing vertical and horizontal normal maps? Can a sim have n normalmaps?

Maybe someone played with this or has come across some code that might explain the index?

[BloomsBase]

Maybe it is like objects, on those the normalmap(read mesh) UVcoordinates are often placed outside the original uvmap.
Those settings are also used to scale a particular part and give it a larger size normalmap.