We finally gave up trying to plan, really. This was unbelievably difficult when homeschooling. We did eclectic homeschooling not by choice but because it was the only thing that we could afford for very long. Curricula would seem "challenging to the point of maybe TOO challenging," then (often VERY briefly, just days) "awesome and fun" and then "not very interesting" (again often just days) and then "completely below level" without warning.
Not even "self-adjusting" software can accommodate it very well-- because she has such low tolerance for "demonstration" once she has mastery. She won't give the 'correct' answers for those next eight or twelve items before she gets the bump to the next conceptual level.
Our objectives now are to improve her tolerance for the world being pretty often out of step with HER (e.g. more patience with "you need to demonstrate" and linear pacing in instruction) and to get her to tap into that inner black box and learn to make it do HER bidding, rather than being at its mercy.
She has shown an ability to do that now that she's 13. That is, she can learn at that super-human rate when she wants to, and not just when it happens naturally. I was very worried about that when she was younger. Because she really couldn't seem to force her brain to engage before it was ready-- or something. I don't pretend to understand HOW this works.