If it’s a flat plane then you could have an alpha material based on a different uv channel and just repeat a fade texture along the edge polygons and keep the internal polys solid.
Exporting as uv coordinate index 1 (0 being a top down projection)
Material setup
In scene
It’s more time consuming but for specific flat models it’s doable.
This is probably the best method form what we’ve talked about before. At least for me that is pretty new to this 
This is the effect of a single layer of shell mapping. Obviously it’d look better with your fuzzy thread material but I don’t have time to recreate it, so this is just with some random noise. But you can see it effectively creates an multi layer look.
This looks like it’s exactly what I’m looking for! Could you show me the material setup?
If using mesh based shells, there is nothing special about the material, other than it needs to be able to tell what part of the mesh is supposed to receive the opacity mask and what parts should be opaque. Vertex colors are one way to do this. For example, the inner surface might have a vertex color of 0 and be opaque, while the outer shell has a vertex color of 1 which activates the opacity mask, not unlike how you had fresnel controlling this before.
Out of convenience, that screenshot was made with overlay materials. I just scaled up the overlay mesh slightly in the vertex shader.
