Smooth paneling with variable thickness?

I’m attempting to recreate an old workflow, using GH instead of @Jarek’s Flatworms plug-in. Aaaaaand failing. I’m able to get a basic outcome that’s close, but lacks the smooth flow from shape to shape, and, most importantly, the variable thickness that Flatworms excelled at. Here’s what I’m after:

And this is what I have so far: (11.3 KB)
Any help would be much appreciated. I think I have the geo internalized properly.