Answer Wiki. The system would be cued off the pilot's helmet, so it will definitely look where your head is pointing, not your eyes specifically (that would be a gaze-tracking system, which AFAIK hasn't yet been used for this kind of application).
Exercise to Gain Leg Weight. Although you can't make your body gain weight in your legs, you can perform exercises that encourage the growth of leg muscle. Squats, lunges and step-ups are examples of such moves that target the legs and recruit a lot of muscle fibers for growth.
Train with weights. Commence a solid weight training program targeting all the main large muscle groups such as the arms, legs, shoulders, chest, back, and abdominals. The extra energy you consume will fuel muscle growth as the exercise stimulates growth. Cut, lose, and shed.