Thanks again for looking into this; sorry I didn't reply sooner, I didn't realise you had posted.
So, for the question of grey items that were previously black, I'm fine with that since I can fix it by un-marking them as known and then making again - I definitely prefer it set this way since I can understand which ones I marked manually.
I'm also cool with not being able to have it toggle at a certain level, that was more of a wishlist idea, I appreciate it wouldn't be simple to implement.
The part where I think we may still be slightly missing each other, and it could be because I have the wrong mental model of how it should work, it that I would prefer, all else being as it is, to be able to entirely turn off the automatic marking as known and just do it manually. As far as I can tell, that feature is the reason why things show up in my vocab schedule when I don't want them to - 格好いい being a prime example of this.
Does that make sense? No rush to reply, I think I can work around it anyway.
Hope you have a great holiday season :)
P.S.
Adding a couple of notes that came to me as I was studying:
To be super clear, my ultimate wishlist request would be for the auto-marked items to stay gray and behave just as they do now, but with the exception that they would appear in the reading questions as kanji (possibly still gray). I'd like them only to go black and behave like black items after I specifically make a choice (representing the point where I feel comfortable that I can write the kanji, which is obviously arbitrary and can't be determined by an algorithm.)
Also, on reflection I'm not sure that the toggle you changed is working quite as expected, which might be part of the confusion - I think the items that had already been marked automatically did what they were meant to, but I think that the new ones were going black, and that was what was causing things like 趣味 and 格好いい to show up black in my vocab even though I hadn't changed them manually.