Thanks for the question. I haven't seen the tutorial, but I would do this a little differently. Instead of needing to split the base spline with a generator for each path, instead you could use a single generator and create the corner pattern parametrically.
In the attached example, Compose operators are used to create the corners. There are two versions to create the alternating rows. 3 segments are needed in each Compose operator. In the first input you add the segment to appear before the corner. The 2nd which is a null, is used to centre the corner on the vertex. Finally, the 3rd segment will appear after the corner. To create the correct alignment I've used Left and Right padding. The padding values are derived from the Z size of the default segment. It's been divided in two and used in positive or negative versions to create the correct alignment.
I hope that helps, please let me know if you have any further questions.