Yep, you need to go a bit past where you need to be to allow it to spring back a bit once the threader is removed...
Luke.
You read my thoughts Luke
Here's a instructable I made about the Sheldon Brown method: http://www.instructables.com/id/Spreading-or-adjusting-a-bicycle-frame/
But as @Falstaff mentioned above: It's better to do this before paint!