We struggle. Part of the reason of why CLOSED in childhood with the kid. Takes up a lot of time/effort.
If you need to schedule D first, then H, that is how it is. Get it on there, fill in the rest, and be ok rolling with it like an experiment til spring term.
Because with all the holiday hoo ha of fall term, it always has a different vibe than spring or summer.
Some life patterns happen on the seasonal or yearly cycle. Not monthly, weekly, or daily and it takes some passes thru to learn that.