Oh. Fantastic. You know which files.
So copy those 4 files to usersc/ with the same filename.
download
https://github.com/mudmin/UserSpice4/archive/master.zip
Unzip it. Delete the install folder, the root indext.php and users/init.php and copy everything into the users and usersc folder. Run update.php
Now, since the files you modified are older versions, there may be a few of the includes (especially on join) that you will have to update the path.
If you look at the new versions of those files, you'll see that they have a more dynamic path that will work regardless of where the file is placed.
I hope I'm making sense with that.
The one thing you'll definitely have to change on those 4 is the init file will have to be changed from 'init.php' to '../users/init.php'
If any of that doesn't make sense PLEASE let me know.
The other good thing is you won't have to worry about those files for future upgrades.