Hi Greg - also you may be interested in this previous message where jonah has a demo of using Blend + array to make something that resembles a sine wave, but is actually more rounded than a true sine wave.

It sounds like in your case that more rounded result would be better:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1519.39

Something like that where you draw just one cycle of your "plumped" sine wave and then repeat it could be a better way for you to build your result rather than focusing so much on deforming an existing sine wave.

- Michael