At 25 I think a GLA tank would be necessary. As a 25/26 GLA I didn't have much trouble tanking any of the 3 bosses, though keeping all the adds occupied (particularly on Shaula) was sometimes difficult. On Antares the adds weren't a huge issue, just get all your DD to target Antares but spam AoE WS with their TP.
Shaula is another story, I too doubt it could be taken by a group of 4 25s, though I suppose that may be the point. You can start the instance at 25, but it has legs that carry it into the mid 30s.
Shaula might be possible GLA,MRD,ARC,CON seems like the most likely group to walk away with a win. GLA tanking Shaula, MRD AoE tanking and off tanking the larger adds, with ARC DDing down Shaula and the CON focusing on heals.
Thanks for replying. This is definitely good information for people looking to complete it at lower levels.
I'm not sure how good meds are in FFXIV, because I rarely use them, but it might that in the case that this fight is made impossible by the CON simply running out of MP, that a few ethers may make the fight possible.
A few meds could really a tip a fight in your favor in FFXI.
I actually used a few Potions during our fights. They don't hurt. I would most definitely use a macro like the one below.
/item "Potion" <me>
In addition, I don't think people should be afraid of using some food if they are lower level. Even getting something cheap with some HP or MP bonus helps out, no matter what your stats/elements are.