For people who can clear the hard gil daily, what is your party setup like?
My party is around level 32 average with an average 7 stars worth of equipment.
The trick is to actually micro the battle and not just auto attack. Most enemies have about 800-1200 hp, so figure out how to do the damage between the strongest members of your party.
On average, each enemy takes two hits from guys doing about 500, so choose the enemies individually and match the people up where appropriate.
Also keep in mind that there are 6 enemies per round and 18 total. Don't be afraid to use your skills, especially as things like thundara will usually one hit kill.