Coil is where you can logically gear all your characters with ilvl 90 gear as well as some of the best gear in the game period. Twintania comes down to your scholar and white mage making sure that the Mr lives through Death Sentence.

Sch main heals tank, watches eye for an eye to make sure it's up 100% of the time and keeps virus handy for when tank doesn't have a CD for DS. White mage heals group after fireballs then MT after, helps dps conflags and stoneskins tank for DS.

If you have a monk they maintain Dragon kick rebuff to reduce pretty much all her damage.

The fight is so easy once you understand the mechanics but it's not to be taken lightly. Requires the utmost attention of 8 people for 13 min which is where the real challenge is at.