How much "more" light and flow? How much is enough?
And I've read the sticky on the cipro treatment, so that's a start I guess.
I think once treated against the infection they often come with they are not more at risk than gigs or the other host anemones.
I also don't see light as the predominant issue as they like to sit on a high spot in the tank where a decent dimensioned LED can serve them well. A Kessil A360N right above it should be fine.
The other things they need is good indirect flow and a rock pile they can sit on. I would also suspect that they need cleaner water than gigs for example since they are predominantly found on the reefs while gigs are more often found in the lower tidal zone.
The more the better. It's hard to overdo it with mags and gigs. People here keep them under T5s, MH, Kessils (350/360), Radions, etc.
If you post a specific light you are using or think about using you may get a feedback here.
As for flow, similar to acroporas.
Biocube is really too small for Gigantea or Magnifica. You can keep one in there but you have to really know what you are doing and find small Gig or Mag to start with. Both of these animals require a lot more flow than the stock filtration provide thus you will end up with bulky in the tank PH for circulation.29 biocube with hydor rotating deflector on output and a hydor 425 for flow.
Already posted lights in a previous post above.