Connect curves and lay out pieces

Hello,

I am new to GH and I am struggling with something. I am trying to create contours in GH from a Rhino model. These contours would then be lasercut to produce a physical model.

So there are 2 things:

a) The rhino model appears to be not solid (naked edges) so the contour lines come out as split. I would need to connect these lines together according to their vertical position. (it is clearer when seeing the model). I tried doing that but they connect in the wrong way.

b) I need to lay them down on a surface which has been drawn on Rhino though when this happens they seem to be not centered on the surface as well as stepping upwards.

I have attached the rhino and GH files.

Please help.