04 Scale

FlexiMotion's collision system assumes that all simulated objects (and their parents) are at a uniform (1, 1, 1) scale by default. If that's not the case, then you can use a ScaleModifier to have it properly account for differing scale.

Note that non-uniform scale is not supported. The scale must be the same on all axes.

The ScaleModifier has references to the FlexiMotion and SphereCollidersModifier components as well as an Is Dynamic toggle to indicate whether the scale will change. The middle character above is constantly changing scale so it has the Is Dynamic toggle enabled while the others stay at the scale they started with so they have it disabled for better performance.

Without a ScaleModifier Scene Gizmos
The effects of disabling the ScaleModifier can be most easily seen on the small character (0.75x scale) where it causes the hair to stick out. If you select that character and look in the Scene View, you can see that the collision spheres are too large because they haven't been scaled down with the model.