1. If you're stat maxing, Earth Eater really isn't that difficult.
2. Maelspike, 200,000 gil, for 1 Attribute Sphere. To compare, Earth Eater is 15,000 gil for 1 Fortune Sphere (2 with an Overkill).
3. If you plan to get 255 Luck, you can ignore Accuracy and you'll only need 35 Evasion. And yes, that's enough to take on DA as long as you have decent equipment.