That link already gives you info on what to do. Although the 2nd link giving you hexediting is very hard to do. What I was trying to imply was there was no program for ff8 that is as good as loveless or makou reactor for ff7 that is easy to use.
Did you check Moomba? It can edit normal dialogues and texts on world map. You can edit battle dialogues, too, but you have to extract text section with hexeditor (it's simple).
Now I work on the next version of Moomba, which can handle PSX version of the game.