This is what I've found with the durability
a) if it's set too low, you'll get the broken weapon message but if you're using this editor, having souls to repair the thing isn't really an issue
b) if it's set too high, you won't get a message and once the thing gets used, it will reset itself to the max durability minus a bit of use
c) if it's set correctly, then everything is fine
I generally do a lookup on the Dark Souls wiki to get the correct durability and only enter the first durability value and leave the max durability set to 0.
It would be nice to embed the durability into the txt files and have them appear automatically in the editor.
jappi, do you have any interest in implementing this if I volunteer to add the durability to the txt files ?