Hi Ben, there may be a tutorial on this, I will have a search, it's been bought up so many times.
What kit are you building ?
EDIT here is a thread with some tips with tune o-matic bridge
http://www.buildyourownguitar.com.au...ead.php?t=3629
also click on this link and scroll down to setting a neck
http://www.buildyourownguitar.com.au...ead.php?t=1895