Nice customs, Tim! I anxiously look forward to your line of Norse deities.
I abandoned authenticity in favor of ease and used the standard lion-headdress klicky for my my legionary century signifiers and cornicens, even though historically this would have only been appropriate for Praetorian century signifiers and cornicens. I also used the same horn you used. I used the grey wolf's head, albeit on the chainmail headpiece instead of on top of the helmet, for my auxiliary signifiers and cornicens. It provides a nice contrast.
