Now that I have a few gigantea-year (number of Gigantea X number of years they are under one care) experience, my opinion is that caring for Gigantea is no big deal. They are, IMO, medium in term of difficult of care. I think Magnifica is harder to keep happy.
Try to care for a sick one is another mater. Getting a healthy one right out of the bag is rare. I think that was why they did not survive well without help.
Stichodactyla gigantea still doing well at 18 months.
More pictures are coming soon.
Yes, it is a grow out tank.
If that's your grow out tank, I'd LOVE to see your display!