I would suggest light to medium contact rather than full on contact. Also, if you are thinking of choreographing a fight break the whole fight down into bitesize parts consisting of 3 or 4 moves each. That way you both know what will happen when you go full speed and won't accidentally hit a blade too hard during the actual fight.
Alternatively, if you're a Sith, just ambush him when he comes out of his room and claim his hilts as your prize!