Follow only the course sessions. No condensed versions, no summaries, no skipping ahead, no changing multiple focal planes all at once.
It’s a suggestion frequently ignored but almost 20 years into this, countless people eventually go “ok so maybe you were right somehow” and go back and just relax and do it the slow and gradual way. 😉
You signed up a while ago though, how far did you get into the sessions?
For differentials, how the centimeter? How long you been using those? Any ghosting / directional blur with them?
Astigmatism correction less important for close-up. Main way to tell if you need it at a distance, check if you get ghosting or directional blur on an eye chart, around blur horizon distance.