Great source. It may be interesting to compare among readers here which portions (if any) they do as a part of their practice.
As to the quoted source I will excerpt the synopsis here for that purpose (for more detail go to Ludwig's link, and thanks to the translators, Ward Rafferty and assistants.)
While it is a useful resource, some cautions should be noted with the text itself. Additionally, beyond those you note, there are some other comparisons that should be made as well:
1) With the same set of exercises as taught at Tsubaki Jinja
2) With the instructional photospread with instructions that Hikitsuchi did for a Japanese magazine ( I don't have my copy handy or I'd provide the reference) in the late Seventies or early Eighties.
3) With practice texts from the groups who derive their practice directly from Bonji Katsuwara
4) With Abe Seiseki's teachings on this matter, both published and unpublished.
In the past, I have gone over Rafferty's text with several different individuals who studied with Hikitsuchi in earlier years. Each has noted what they considered significant divergences between his presentation and what they clearly remembered being taught, and their memories matched up with one another much more closely than with his text. It is also clear that significant portions of this "translation" are not direct translations of Hikitsuchi's practice instructions, but are the translator's autocommentary and associations with his own prior religio/spiritual experience, some of which represent clear misunderstandings at best.
This last is a problem that is not unique to this text. When I was studying with Professor Ryuichi Abe, he used Michael Saso's "Tantric Art & Meditation: The Tendai Tradition" as a cautionary example of just this sort of problem, a problem which has been compounded by other authors drawing on Saso's work, in connection with both Tendai Buddhism and aikido.
There are also multiple problems of appropriate introduction to/initiation in/ritual binding of
these practices that go to the pragmatic points Mike Sigman references, as well as a host of other key instructions that don't appear in any publicly available text on these practices.