JimmyT, no question that five voices fill things out--smaller groups can get to sounding very thin around the edges, especially when one voice is holding back--

I had a chance to hear Brian Wilson when he did his Pet Sounds with Full Orchestra tour--not only did he use the five parts, he often had two voices covering each part! Quite a contrast to the shaky sound the "Beach Boys" had when I last heard them back in the 80's--