Ultimately, I guess that might be possible, but no one ever succeeded to do a thing like that on an ISO for what I know. The problem is that adding more characters means "pushing" the datas in the file and it doesn't like it.
Fortunatly, there is an extra space empty and unused after the text dialogs (it varies between 0 and 2048 extra characters for one text block). So I can use that space.
The only cautious is that I don't know exactly everything about how dialogs are encoded and I just need to do some tests to get it working well. I'm not planning on pushing the limit more than that.
Also, keep in mind that a lot of the texts in a text block isn't actually used (dialogs from CD X but present in CD Y, debug dialogs, etc...).
I can't reproduce the "overwrite save datas" bug. Does it happen even if you only edit a spell's power? Or is it related to text?
Did it re-scanned the file? The .hwf should be updated. If that's the problem, just delete the .hwf file and let the program redo one.
@shikulja : I think "Cyrillic basic" is meaningless then, since you have already the good font everywhere else (that wasn't the case in your previous screenshot)...
Anyway, I'll try to be a bit faster on the next version, so everything can work properly.