You could instead just forge 50 more clams / turn .
Or forge 7 gears for SCs/thugs per turn if you use all 7 items on your SC/thug .
A caelan mage is imo so cheap that it is a complete waste equipping him .
I would probably do 50 extra clams / turn . That is 1 extra wish every 2 turns . Just wish for blood or EliteScs and win the game with that .
Cause if you give your mages a weapon + a shield then you should also give them a ring of fire resistence and an armor to avoid flames from the sky and stuff like Earthquake/Falling Skies .
Caelums mages are so cheap but as well physically a bit fragile . You have probably something like 50 castles already so you could build 50 new mages every turn . So just don't mess with equipping them
.
It is imo one of the worst investments you can do in dominions 2 ( expect in the special age of men game and games with similiar houserules ) .