Cutting Shapes beneath an uneven Surface

i am struggeling to create a model where i am cutting a shape beneath an uneven surface.
I tried two different methods of creating the shapes but neither is giving me proper results. The jumps for the two different methods are located in the top-Left corner of the file.

Method 1:
Method 1 is alot cleaner, easier and faster than method 2. For method 1 i move the projected curve along the vector to create the shape. owever upon baking the results you see that the bottom of the two plysurfaces doesnt line up.
Method 2:
For method 2 i move the points at the beginning/end along the vector to create the shape. Then i connect those points with lines. As of now i create the very top surface with the curves (Test 2 - Jump 2).The bottom of the new polysurfaces now lines up, however the top of the polysurface now does not line up with the uneven Surface that is supposed to be the top.

Both poblems are due to the very uneven shape of the confining top surface. My only idea for method 2 so far is to create additional points between start and endpoint. That would be a very tiresome way which only solves half the problem.
I hope i described my problem coherent. I would greatly appreciate any ideas you have for me!

Apologies for the messy file, im pretty new to Grasshopper.

Sincerely Nils (1.0 MB)

very curious what this is, anyhow to me it was totally unclear from the file and description what your issue is. Maybe it is a better start to tell the goal you’re after. Seems to me that it your file is overly complicated for what you try to achieve.

Thank you for your reply, i cleaned up the file to give a better idea what my problem is.
Now only method 1 is depicted… It shows two sides of two shapes that are supposed to align just under the confining top Surface. However the bottom of the shapes doesnt line up, as can be seen in the screenshot. Any ideas how to fix that?

Regards Nils (759.0 KB)

I don’t have time right now to look into this, but if the shapes are allowed to be changed, I would model everything with simple boxes and later deform the shapes to these boxes.