For the record, to tag a user, it’s not just copying the hyperlink for the person. It’s to put “@“ and type the name behind it.
Now, I’ll probably be able to give you the rough addresses for where IV is, in comparison to the species, later. Watch this space.
Edit:
According to my records, it is - 0x0B from the location of the species.
Do a few tests, you should find it. When in doubt, load the edited file in my program and check if the changes are there.