One of the theories of rattling is that when a buck hears the clashing of antlers, he investigates to find out if he can steal the doe when the other two bucks are fighting; not necessarily to join in the fight. A wise old buck will definitely investigate a small set of antlers being clashed. On another note, if you use antlers that are too large, a "good" buck might not come in because he suspects the two bucks fighting are larger than he is and he feels intinidated. That said, use the smaller antlers.