Well there's a Pre-mastered Gravity with a high Magic from one of the missions. (9-3-3. Comes with +42 Magic). And you can get Graviga from a shop (Bone Village Commerce), a chest, or from several missions as a reward.
I lack skill, not knowledge. Disclaimer: All posts reflect MY opinions, not yours.
pheonix downs are really rare though right? what's the earliest place to get one? (I remember I only had one at the end of my game, granted I ignored missions and just wanted to see the story, now I'm doing everything this playthrough)