Ah, with the Character command the attribute has a different name - it’s called
Strength Multiplier and should appear at the root of the blue control hierarchy.
What you’re looking for is either (1)
Guide Strength on each individual rigid, or (2)
Guide Strength on the
rdConstraintMultiplier node type.
You can find all multipliers through Python like this.
from maya import cmds
This will select them all, only one if you only have one character. You can then either edit the individual
Translate/Rotate Guide Stiffness or follow the connection to
Guide Strength to see where it’s going. It should be the root of that blue hierarchy.
I’ll fix this attribute name on Character’s. It should be called
Global Strength like it does for chains.