Okay I have seen a thread about hacking ff3, but people are trying to use addresses from other peoples games and then they don't work.
Firstly any attributes on a player ( xp / current HP / max HP / current map / max map ) change addresses when the job class in game changes.
If you edit a players xp as a ninja and then try and use that saved value when your a dragoon it won't work!
Codes are specific to player then job class!
Gil however is constant.
So far I have edited the following with the current apk
All players current HP and max HP.
Edited the amount of xp you will receive after a battle ( separate code for each player )
Number of items in the inventory
Job level for player and job class equipped.
I can't even use saved values from a previous play of the game with the same player set up and use the values that way.
But its easy and works if you do it manually every play! I can set HP to 999999999 as the max health which helps with the final boss!