There is 1 option for a dwarven male hood at the moment. Because helmets are unlikely to have facial-parts added across the board, or ever be dynamic, my suggestion is that we use some of the head models that are already available as -hood options to represent a dwarven male wearing a half-helm.
For example:
-hood (uses the default hood)
-hood 1 could use head 18
-hood 2 could use head 20
-hood 3 could use head 26
Purely an aesthetic and RP assisting change here, which wouldn't require any new models or animation, only a slight script adjustment for -hood command on male dwarves.
