right am a wee bit stuck on the aeons i've decked valefor, ixion, ifrit, shiva and bahamut but cant get past the magus sisters lol anyone know what sort of level me players should be at for the fight ( think am currently about Lvl 50. ) any hint's would be appreciated

I was around level 70 by the time I reached them, and I found it easy once I took out the smallest one.

Though she has the highest evasion stat, she also has the lowest HP of the trio - you should attack Mindy before the stronger two. Killing off one of them will neutralise their pain-in-the-ass Overdrive, which will hugely benefit you - naturally.

Protect is a good White Magic spell to maintain throughout the fight, as Mindy is the one of whom casts Black Magic often. Without her in the picture, you'll need only put your main concern with their physical assault - which will be significantly lessened should Protect be active.

Regen could be useful to you if you find yourself frequently with dwindling HP; might just set the line between losing and casting that needed healing spell.

And finally Haste. Though you should only really bother casting this on two of your party members, as 3 castings is a bit of a time-waster. Your White Mage/healer should have be buffed with it, along with your hardest hitter. Use Dispel when Cindy casts her defensive spells, and the rest should hopefully be smooth sailing.