The right amount lies between deficiency and excess, between too little and too much. Virtue is behavior of high moral standard that is done to benefit well being, that is, is done for growth. For me, if a behavior is not intended to further growth, it's not virtue. If the action is too much or too little it can still be virtue if the action was done with the intention of facilitating growth (even if it doesn't). I find virtue in balance when the action intended to foster growth is just the right amount. For example, giving exactly the right amount reempowers and facilitates growth, giving too little doesn't help or helps little, and giving too much is likely disempowering or disrespectful which also doesn't help. What helps you know the right amount is paying attention to the other, respect where he or she is at and what he or she is saying, and pay attention to your own experience and judgment.