[Lazy_Perfectionist]

I hadn't noticed the mystics had a chance at fire, along with the mage engineers.

I don't particularly recommend this for arco, I'd ruther spend gems on air elementals before I'd forge eyes of aiming on a nation with powerful air magic, but its good for some others, and you can use Wind Guide as effectively, I believe. Moreso, perhaps, because you're not wounding your mages to put it into use, and taking any attack or defense penalties.

Units with 8 to 10 precision capable of casting magma bolts will benefit greatly from an additional five precision. Most earth magic has a short range, however, and you might not be willing to move your mages so close to the front lines.

You won't get pinpoint accuracy, but bolts will be much more tightly grouped, and you'll be fearing friendly fire less.