You can't really read things in your peripheral vision, you can just kind of see patterns. Andy speculated that the subconscious can probably pick up these patterns and that it helps your intuition of when to dip, but even if it doesn't there's enough indicicators in your conscious field for your subconscious to go, "oh, this is the section about annelids; screw it, keep going, man, you don't need this to fufill the purpose you stated".
As far as soft focus and diverging, here's how it goes:
If you get a blip page, your eyes are either diverging or converging. If your crossing yoru eyes, it's converging, but if you're letting your eyes relax (the right way) your diverging. In other words, if you're not crossing your eyes and getting a blip page, you're diverging.
Soft focus and hard focus is a little harder to describe. It's kind of independant of diverging and converging, since you can diverge and get the blip page without having soft focus. I can't really describe it, it's like everything you see becomes softer or the tiniest bit fuzzy, though everything is clear. It's hard to describe.
But it's easy to feel the difference, and in general, with hard focus you're focusing on a small single point and have a tightness in your movements, whereas in soft focus your perspective is generally larger and you're relaxed. Use the tangerine techniqe, it helps to get a soft focus.
On peripheral vision - everybody has it, it's just that some pick up on things in it better than others...it's just that we refer to the ability as peripheral vision as well. Basketball players have excellent peripheral vision, because they have a knack seeing teammates in the corner of their eye without moving their eye or head, and passing to them. Some if it is based on prediction, but some of it is peripheral vision.
My wider peripheral vision is kinda junky since I wear glasses. But as far as soft focus goes, I'm not bad =)
I know this is confusing. Don't worry about. In overall answer to your question, your mind can still guide you when to dip if you're not consciously seeing words on the far left or far right.
-Ramon http://razor.ramon.com