I'm not really sure what the best weapons are... I don't have wi-fi, but I have 2 AR codes that helped me through the game:
All Jobs
94000130 FFFB0000
D5000000 00000101
C0000000 0000000A
D7000000 020B77CE
D2000000 00000000
Job Level goes to 99 after you level it up one
02019858 00000000
These work on the English version as far as I know.
I'm sorry if I have broken any rules.