Before you get started, I'd highly recommend popping to the market board and picking up two Cryptic Seals if you're a non-caster, or three Damascene Cloth if you're a caster. These can be turned into an NPC near the Pier #1 aetherite in Kugane called Nostalgic Fellow. He'll give you a chestpiece with Elemental Bonus on it, which increases your damage done and decreases your damage taken in all Eureka zones. Note for Materia players: Prices for these materials are extremely high currently due to lack of supply. Prices will come down as people progress through Eureka and start running Baldesion Arsonal but for now, if you're not rolling in gil, I'd suggest skipping it. The bonus is nice, and the chest-piece you get remains Best in Slot for all Eureka content, but it's absolutely not essential.
You can get two more pieces of magicite, but that involves a lot of farming, luck or gil. If you're chasing just the armour for glam, forget about this.
[Eureka Tracker