Mark, Thanks again for your very kind comments. That arrangement is based on Manhattan Transfer's recording. I didn't try to copy it, but I definitely tried to mimic the feel. They are way "up there" in my harmony professors. Earlier influences include the Four Freshman, The Beach Boys, and more recently, Pentatonix. Addressing 4 parts is very different than standard 2 part harmony, like the Everly Brothers, or Simon & Garfunkel. The lead voice needs to be simpler, less affected (vibrato, scoops etc) and dynamic expression is crucial to the believability. It's very much like working the expression pedal on an organ - the up, and down regulation of the volume is as important as the subtle bends on a guitar string ... it's happening ALL THE TIME in some way. This is why many singers avoid using compression on their vocals. Misuse can severely affect dynamics.