For fast chromatics, I play the black keys with flat fingers for most of the passage, and then I use curved fingers at the end. I use curved fingers at the end because you get more control over how you end your chromatic, so you can a clearer sound the moment you end the run. Using flat fingers on the black keys allows you to keep your thumb almost rigid and only bent in one direction, so it takes less work to hit the keys with it. (Question to CC - is this similar to the TO method? I'd never seen it used, so aside from your written descriptions, I'm not sure what it's supposed to look like) I use a lot of wrist movement because when I transfer to the next set of black keys (i.e., from Bb to B to C to C#), I revert to curved fingers.
However, this is a method which developed on it's own, it feels natural to me, and it produces beautiful, glissando-like chromatics. It's not necessarily the best method for anyone else, though, but it's something to try if you've already been having difficulty with fast curved-finger chromatics. And I only use this method in long chromatic passages - it is not needed for quick runs, in my own experience.
Mentally, I always "aim" for the top note. Basically, I tell myself that I want to hit a single note, but my hand is two octaves over there, so the only way I can get to that note is to play all this junk in between in as little time as possible (when there isn't a strict beat to set the speed).
Good luck!
Motrax