[Xietor]

As to the suggestion that he should have had one of his mages cast a spell that cost gems, sometimes when you fight 3-4 fights to get to a key battle, you mages have wasted all of the gems you give them.

Say you want a nature mage to cast mass protection, but no other spell that used gems. Unless there is a command i do not know of, typically the mage will waste all of the gems he has casting spells like swarm etc.

I guess one answer could be to give nature games to another commander, and ration the gems to a nature spellcaster, but if you hate micro managing, then that would be a pain.