I was wondering if I could offer some ranking structure for the mages.  They are more ranked in terms of magic aptitude and battle experience. 

Initiates-0 to 2 years and are the lowest magic users
Novices- 2 to 8 years
Adepts- 8 to 15 years
Masters- 15 years and over (this could be further subdivided if need be)

Regarding actual command or rank perhaps it could be a Bleach sort of structure i.e. First seat etc?

Also, perhaps rank symbols could be based on their robe color?

Initiates-white
Novices-grey
Adepts-brown
Masters-black

Stripes on their sleeves could denote rank