[AreaOfEffect]

I've played with the sprites before and they worked out fine for what I was doing. Though I admit that was a little while back. They may not be cataloged, but a little play testing will help you locate the ones you want easily. Just know that sprites are grouped together into similar effects with different coloring. Use a battle where you used the spell and just reload it after each adjustment as the sprites will change accordingly. Its not as bad as creating a unit graphic one pixel at a time in my opinion.

I would imagine that, for the developers, the creation of new battlefield spells would be easier then making new summons. Assuming they've documented their work in the slightest.