It's been years since I read Writing Down The Bones, but I own Wild Mind. It has more exercises and the like, and is more practical, so I'll go with that one. Obviously, YMMV, but even years since I read either book, they stay with me and I go back to the exercises I read in the books 7-8 years ago.

Also, yes, I'm a big advocate on doing what works for you. And for me, writing like a mad thing and not worrying about them being perfect is the best way to get past the critic.