For more information and pictures of the valve stem seal replacement and also the HLA replacement and cleaning, I remind you please check Funji's projects on both topics where he gets much more specific. This project should just be used as a rough guide to get you in the position to replace the valve stem seals as Funji describes.
Comments can be found here:
http://www.mx6.com/forums/showthread.php?t=120765 (Comments on: Replacing valve stem seals with head on car)
mrfunji's thread can be found here:
http://www.mx6.com/forums/showthread.php?t=39955 (Rebuilding Head)