I wouldn't consider Carl Jung the absolute authority on Astrology, although he contributed much to the study esp. the collective and psychological astrology most Tropical astrologers practice.
By "Decan" I meant exactly that, as you mentioned; i.e. Sidereal positions. (See McKinnell's Macro theory regarding the Age of Aquarius on the Decans)
I do think too, that full blown Age of Aquarius will be later rather then earlier (as in our lifetimes)....But who knows for sure?
Just futurists, perhaps from other times and places as to what happened to the United States and the world.
Many many years ago I use to communicate with Terry McK. about his theory. And believe me as a Sagittarius Sun he is just loaded with words and theories concerning his well oiled "Age of Aquarius"....Unfortunately, although I was intrigued by both his knowledge as well as his fortitude to stick with a subject unto forever (or so it seemed to me) to invest this type of work, time and effort into one subject matter, I think he could easily qualify as a first class researcher into the subject, seemingly leaving no rock unturned in his quest.
I use to have his natal chart (so fascinated was I by his fortitude and sticktoitiveness; but long ago must have lost it. If anyone else has it, I'd be interested again because I'm sure Gemini must be in there somewhere, lol.
He was one of the first western astrologers to introduce the Macro-decan theory in the western tropical world or was he concerning the advent of the Age of Aquarius ? He is so fast, so quick in his commitment to this cause, I simply lost interest and couldn't keep up with it all. AND, thats saying a lot, because I too have Sag Venus (brings scattered and wide ranging interests) as well as Gemini Rising (Sidereal chart) He IS one of a kind, imo. (*appears
his Moon would also be in Gemini, in both charts different degrees of the sign) Ha, I thought so!
I found his chart here:
https://www.astro.com/astro-databank/MacKinnell,_Terry
Looks like this page also shows a YouTube Video if anyone has the interest:
https://macroastro.wordpress.com/blog-index/
Video:
https://www.youtube.com/channel/UCV9VUTL08iWz-WatiwYxHeQ/featured?platform=hootsuite