I really like that players have the choice to lower or raise their sanity on a change. There is a lot more flexibility here for the group to keep things from getting offensive or to prevent the narrative from ending in an anticlimactic disaster only because of bad rolls.
This might be the first sanity mechanic that I would like to try at the table!
The one thing I'm missing is a big spark table for more character-, clues-, and especially weirdness-inspiration.
Maybe with the same multifunctional structure like the big table in your game Dark Designs.
So, if you'd ever decide to make a one-page supplement for Sanity, that would be my pitch.