Ok here it is, here is the lucky 7 way i get by my self i hope you like it.

- First of all you'll need to equip your transform materia ( see Materia page if you don't have it ) then you
must go to the beach part near wutai. There you'll find a big turtle that only casts barrier on himself so you'll be free to do whatever you want in the fight. Ok, now you must cast mini on yourself (or in all your party if you like) and then hit the player you want to have lucky 7 until the last two numbers on his hp are 77. after that all you've to do is use hi-potion and potions 'til you get to 7777. that's all.

Hope u like my way to get the lucky 7 =). Bruno