Need help with extruding lines at a tangent derived from curve!

Hi everyone,

I have a question about extruding according to a tangent. Or maybe a derived vector might be a more appropriate.

I have a bunch of curves but I can't seem to extrude them in Rhino. Well one option is to explode the curves, loft them to fit that profile and then join the surfaces and offset it as a solid. But seeing that this is time consuming and might get messy, I was wondering if anyone knows a solution to this?

The red arrows are the direction I want the curves to extrude.

Would be great if anyone could give some pointers or tips!

Rhino file attached below

Cheers,

Ra