Gear is more important. I had Vert at 40 and she was the main damage dealer. Get the following:
CPU Ring design (Hello, So Shal Forest chest) Magical Fragments (Lastation, Soni Wetlands, Heavy Dragoons) Cool Boxbird Wing (Hello, So Shal Forest, gather during harvest shift) Flamin' Petal (Leanbox, EM ES Magma Cave, gather)
Make for all, 200 STR INT AGI, 2500 HP, 1 MOV 50 fire/thunder resist
They cost 5m so either farm invisible cloths to make clothes for money or just farm lots of the mats. They last forever so...
Dreadnaught design (Planeptune, Leggo Island) Iron Shell (Planeptune, Leggo Island, gather during harvest shift, or scout 10000) Water Crystal (Planeptune, Leggo Island, gather during harvest shift, or scout 10000) Pink Ribbon (Lastation, Rud Arms Sewer North, Cold Girl)
Take Vert, Plutia, Blanca, whatever, pair Nepgear with Vert.
Spread out and spam Sylhet Spear with Vert. Plutia should use her Meanie Face debuff from the 7 designer quest. Everyone else is supporting with heals, hero drinks, str buffs or guard breaks. It doesn't regen so just stick with it.