First plateau: At a dosage of 1.5 to 2.5mg/kg, effects include alertness, restlessness, increased heartbeat, increased body temperature, intensification of emotions, euphoria, loss of balance, and slight intoxicatication.
Second plateau: At 2.5 to 7.5mg/kg, effects are similar to the first plateau, but with heavier intoxication, choppy sensory input, a dreamlike state of consciousness, some detachment from outside world, and closed-eye hallucinations.
-Taken from Bluelight DXM wiki.
So me 100kg into 480mg would be 4.8mg/kg.