Hi, I'm working on these abstract trees that need an accurate 6mm deep 16mm wide channel cut out for the LED track. I've tried doing edge-to-spline>sweep a rectangle>boole out approach, but sweep gets twisted around, of course, not following the normals of the tree. To make a rail spline would be super tedious, probably not accurate enough as well.. I've tried subdividing the spline but it limits the width to nearby edges, not giving me 16mm width.

Is there any other, more advanced techniques I could try? So stuck! Appreciate any help

See streenshots
https://drive.google.com/file/d/1_ed53qFViDkb1EXxmBwfgO4TTDIT0b4x/view?usp=drive_link
https://drive.google.com/file/d/1Pi7736P8iUNCrnRt-b7NsFFH1qE0sC9m/view?usp=drive_link