I find that the slower the movement, the more the pace you should go is dictated by the sound of the piano. If it's relatively bright with a fast decay, you need to go quite a bit faster than if it's mellow and the notes hang around.My suggestion is to find the point where the pulse doesn't break and go a little faster than that.
Off topic, but I noticed you wrote in your blog that you had prepared your "three volumes" of the sonatas. I've never heard of them being separated into three volumes before - usually two. I'm curious to know which publisher this is