I am fuzzymillipede. Welcome to my page.
I have written a save-editing utility for all versions of FFX, called FFXED. http://forums.pcsx2.net/Thread-FFXED-Final-Fantasy-X-Save-Editor-on-a-Real-PS2
My favorite pagesEdit
FFX Sphere Grid IndexEdit
Here are maps of the FFX Sphere Grid that show the order of all the nodes as they appear in the game data. If you want to edit the Sphere Grid in FFXED, you will need to use these images to find the nodes you want to modify.