aaand this shows that I didn't understand...
Yes, s-on/s-off and root are two different things. One refers to write-protection and the other to privileges.
The reason I say they go hand-in-hand is that permanent root can not happen on this pho...
Here's what I do. Buy Root Explorer from the Market if you haven't already. I'm sure you could do it with other programs, but in my opinion Root Explorer is the single most indispensable app for root users so you might as well get it anyway.
Check out Reader HD: https://play.google.com/store/apps/details?id=com.ageofmobile.reader
It does what you want and is more customizable.
Photos of dust under screen: