Both level together. level one you level the other. If your summoner is your main but has 1h+ waiting que well I personally use Scholar and nver wait longer than 15 minutes. So what happens if my main job weapon drops.

I can't need it. I can use it. I want to use it. I need it for the main I do stuff with. However because of the glut of DPS jobs people love I have to use Scholar rather than stand around doing nothing for hours on end becuase Chocobo is locked away.

Why rage now? Finally beat Garuda. Finally. Summoner main weapon dropped and went to a Dragoon who wasn't even leveling the damned job. And what was truely insulting? She apologized. If you're gonna feel sorry about doing something on purpose. DON'T DO IT.