godbyk

I think Lilypond <https://lilypond.org/> is the TeX for music engraving.

For typesetting short snippets of music notation within TeX, you can use the MusixTeX package <https://ctan.org/pkg/musixtex>.

Well, they didn't say 'cable TV cable'. They said 'cable TV-style cable'.

Perhaps \bar{z} instead of \overline{z}?

Letterspacing and kerning are not the same thing (as explained on the page you linked to).

In my experience the TeX engine has decent error messages. The LaTeX set of macros, however, do not. What happens is that LaTeX doesn't do as much error checkout at its higher level of abstraction and leaves TeX to sort it out. TeX's errors are correct but tend to refer to the lowest level of code—the least helpful pointer for the reader. It's akin to the error messages you see from a C++ compiler about template functions.