It should be noted for future browsers on this thread that your attachment is a PDF file, and not an image so that's why it's not showing up with the image command.
http://alarmrobotics.wikispaces.com/...e/Forklift.PDF
^ correct link.
That said, it certainly looks feasable. 10" should be more than enough overlap with a 3 level system.
1" overlap = very bad & unstable!
Your 10" should be about right if not more than enough imho.
Good luck!