I am ashamed to admit this but I've spent a lot of in-game money on this game. A lot. Probably in the hundreds....but only during FF8 and sometimes FF7 banners (like that's an excuse).

My main party is:
Squall with cutting trigger and SeeD uniform (lvl 75)
Rinoa with Valkyrie and mystery veil (lvl 61)
Y'shtola with light staff and healers robe (lvl 60)
Thancred with betrayal sword/thief blade and ninja chainmail (lvl 62)
Seifer with hyperion and esthar bracers (lvl 60)

although I often switch in:
Tifa with grand glove (lvl 55)
Sephiroth with masamune (lvl 64)
Cecil with dark sword (lvl 51)
Zell with metal knuckle (lvl 55)
Aeris with metal rod(I forget) (lvl 60)

Heroics+ is really challenging but if you hone your abilities, not dying is a lot easier xD