I worked on this a little yesterday.

First off, the model is a mess. Not quite sure how it was created.

I rebuilt it so i could generate some results.

The 2 surface michaels shows in his last post have an opposing draft angle that also crosses over itself half way through the height of the model.

A single surface in that area will never be “smooth”

We can create it without any “hard edges”, but it will have to have a wonkey wiggle that compensates for the opposing draft angles.