Guest Adder Patch and Events

The famous and wonderful - Guest Adder Patch.

Now the questions, how does it actually work? Not the gritty details,moreso how does it work during an event? If the linked item is in the inventory, does the character that is setup to be added actually directly take the place of character slot 14/15? Or does it just add the character to the selection screen in place of that slot?

The other question: Does the exp and level of this added character save if the item is removed from the inventory for a period of time or is the character created and level balanced every time the linked item is put in the inventory?

The reason for the question? I need to know just how much I can abuse this patch during a event. If I do an event queue for character 0E will it access the added guest or the original character slot 14?