Ok so I would really like to do tetras for my necromancy tau force. So in other words in a tourny setting sanctioned by CAG...I would need to have the imperial armorial book that they no longer make or the sanctioned ga stamped Pdf file to use it. Am I correct? Just trying to be straight on the ruling. Seems like forgeworld took down those printed pdf files and I can no longer find them. However they are correct on army builder.