Well you can't have an option for where the option file with the option is.
I can have the installer adjust the shortcuts or whatever but that's about it, and I dunno if new people will grog what a "Data Folder" and "User Folder" are.
How about this:
If a custom save location is desired, then yes, adjust the shortcut on the installer. If no save location is specified, then by default it should look in the users home folder (for each respective system supported)
I would leave the data location command line switch as an advanced feature that under normal use ... wouldn't be used.