Help with boolean and extrude?

Hi everyone!

New here. Umm, I'm having some minor problems trying to make some balustrades. I've been trying to use the extrude and solid difference components to get my balustrades going. This is the sort of result that I am aiming towards:

This is just a sketch i did in rhino. But I do want the result to have thickness in it.

There are 4 long curves where planes are constructed by lines along points along these curves. These are lofted and they create a bunch a torquing planes. The arrangement of the points are controlled by a graph a made in Rhino plugged in by grasshopper. (Not sure if this matters, but anyway) I'm trying to extrude those torquing planes, following the same angle they're at and then boolean it by a solid created by lofting and extruding offsetting curves inwards.

I'd be really grateful if someone could please have a look at my definition and rhino files to tell me what's going wrong or whether there's another way to approach this (apart from modeling it up on rhino 'cause they will probably change).

Also thanks in advance!