[Vwdiesel] head bolts

[cass]

hi kids.
i am a little worried here,
:o/
how many different types of head bolts are there for diesels?
specificly..are then any length differences?
i knew there were 11 n 12 mm.
the allan head type n torx like head.
and are there incompatibilities with some *heads* with these bolts sizes?
(wondering if i shoulda re-built the *other* head :o/  )

thanks
cassie.