Problem is, Azbat was only around for a short period of time and he evolved constantly from issue to issue. Add to that that different artist drew him differently, with slightly different color schemes to his gear, and you're left with no bottom-line costume to say that this absolute "HIS" costume. You can honestly pick whatever stage in his development that you want and be right. If you want to go with a mask, you're right. If you want to go with a helmet, you're right. He wore both at different times. Just choose what you think you'd like to invest into building and like having as a finished product. Just be ready for the work involved.
Good luck.