This Scaler include :

Arm "lfClavicle/rtClavicle"
Avatar Size "PelviseNode"
Shoulder "lfShoulder/rtShoulder"
Thigh "lfThigh/rtThigh"
Hand "lfHand/rtHand"

Click "debug" and then "Debug 02" and simply change "ScaleAbsoluteX, ScaleAbsoluteY and ScaleAbsoluteZ" value under each NodeName to change each bone size

1 value is 100% scale, so for example if u want to make it 90% then the value would be 0.90 or 1.20 for 120%