Among the HSers I know, there is a wide range of curricula. Besides Michael Clay Thompson, others have used and recommended IEW (
http://iew.com/) Institute of Excellence in Writing, Write Source (
http://www.thewritesource.com/), and Essentials in Writing (
http://essentialsinwriting.com/). I feel comfortable with teaching writing myself--and also have a reluctant writer who would melt down if asked to engage in lengthy writing (especially handwriting) on a regular basis--and so have chosen to use more stripped down materials, such as Evan-Moor Daily Six Traits Writing (
http://www.evan-moor.com/p/2017/daily-6-trait-writing-grade-1), which prioritizes frequent small (15-20 minutes) writing exercises that break down the specific attributes of good writing, over lengthy long-term, big picture assignments.
I also, as I have mentioned in posts to other threads, de-couple the components of writing for focused instruction. E.g., at different points, handwriting, spelling, punctuation/capitalization, syntax, idea generation, organization, elaboration, word choice, etc. have all been scaffolded so that one of the other components could be the focus of my learner's attention. We generate written products using both handwriting and assistive technology (word processing, speech-to-text, scribing).
And I should note that it took me a few attempts to find a curricular approach that was suited to each child, especially the putative 2e one. We started with more conventional classroom-based curricula from big box publishers, which were not only minimally effective, but reinforced negative attitudes toward writing, very briefly tried, then abandoned, "classical" approaches, which tend to be copywork-heavy, did self-created work on the writing process and the 5-paragraph essay form (that one might have been too ambitious on my part, for that stage of development), and then finally settled on Evan-Moor. (They also have other writing products; I just like this one best for my DC.) Your journey may take a different course, and find a different optimal fit.
