Coteaz = co-tee-az or co-tez?
All the Germans over here have no problem pronouncing the 'tz' of tzeench the same as the 'tz' at the end of gitz.
A friend of mine insists it's ae-giss and not ae-jiss.
See here for correct pronounciation of 'git':
http://youtu.be/_EfW9znJYjw