Well, the only way you can really get a feel for items is to forge things and try them out in combat. So don't be afraid to experiment. Like I said though, I would recommend at least hitting Construction 4 if you want the items to be actually useful.
The more mages you get the better off you are actually. Any mages that you don't actually need in the field can be researching to improve your magic. Some nations can use mages for leading armies too, and basically dont need to recruit any other commanders.