Surface from mesh

Hi, i know this is probably the long way round,
But i tried to convert this mesh into a surface by intersecting it with lots of lines,
And lofting the resultant lines of points.

It works, but the surface created is so complex and large, that i can’t work with it.
Is there anyway to simplify it or the process?

I eventually want to offset it horizontally to create a 3d printable solid.

Thanks (112.5 KB)

inner wall.stl (220.1 KB)

Pufferfish has a component called Mesh to Polysurface.

And Weaverbird has wbThicken, which you can use to give thickness to your mesh. Then bake it and export as .stl