Change the size of any field sense safebox, inventory, dragonsoul, take much more code than that will make. Take the tutorial indicate for LordZiege:
Dependes how many slots do you want to do, you must to change variable type in soucer game, db and binary, DataBase fields, and client side changes to.
I make my own changes in safebox, now i have 6 pages of 9x5 slots any, 270 slots, i dont chance my inventory, but takes similars steps.
If yu want help, PM me.