Please forgive me if these details have been posted in a previous thread (I searched around and didn't find it).
My red pixels were off at least two pixels in some areas. My projector is ceiling mounted and the lens is only two or three inches from the center line of the screen and about four inches below the top of the 100" screen. The lens is about 11.5' from the screen.
When adjusting the LCD alignment with a ceiling mount, you need to remember that things are opposite/backwards--in other words, when the square starts in the upper left corner, you adjustments are actually affecting the upper right corner. When you are doing the cross hair adjustments, you have the same situation. For example, if the cross hairs are on the the second intersection from the left side of the screen on row two, you adjustments will impact the second intersection from the right side in row two.....and so on and so forth.
I spent about an hour adjusting the red and blue pixels and now have all parts of the screen within half a pixel alignment.
Most of you guys are way ahead of me on projector knowledge, so I'm sorry if my explanation is too elementary. I hope this helps!!!!