Hi Gregarious,
I'm actually working on something very similar. There is no "Magnet" type tool in MoI. But I'm about to switch my initial curve. The sine tool will give you to many points to be able to acheive what you are describing. I'm going to re-create my sine with a simple drawing tool, thyen I can show the points and deform it in the 3rd dimension.

The other thing you can look at doing, is creating a surface that has the "Plumping you want/need. with a sweep of a couple of curves, or just extrude a plumped curve, then "project" your sine wave onto that plumped surface. If you know your sine wave is fine at this point, this will be very fast. But if you may require a bit of adjustment down the road, you'll kindof be stuck now with the multitude of points, all plumped and hard to deform. You'de have to revert to before the projection to make an adjustment.


Good luck!