These are really wonderful, Jon. Thanks for doing them and posting.
Thanks, Jack! I've got a bunch of other tutorials in mind along the same lines, and I might make a dedicated page on my site just for tutorials so they can be better organized. Feedback is welcome, especially if anyone encounters problems following them!
The tutorials are all based in markdown / liquid templates, so I may fork them out into a public git repo that just gets included in my site's private repository.