Using private (i.e. "not shared") is probably best.
Note that shared vs. private simply changes where the config files are stored on the user's machine. In private mode they'll be stored within the user's profile folder (as part of the roaming profile, if you are using one). In shared mode the config will be stored somewhere visible to all users on the machine.
(Note that shared mode doesn't do anything across machines unless you manually redirect the config folder to a network path.)
So if you want different config for different users, private mode is the way to go, definitely. Although if you only ever have one user logged on to any machine at a time then you could use shared mode if you really wanted to (by changing the logon scripts to overwrite the shared config).
Whatever you do, you can automate things by simply copying the config files to the appropriate places. There's no need to manually run the Backup & Restore wizard for each user (though if we're talking about a handful of users then that might still make sense). Info about the configuration file locations is here and here.
The config data is almost all in text format. Sharing config files isn't generally useful, though. People are unlikely to want all of your Preferences settings, especially when they have no way of knowing what will be changed by importing your config.
If you want to share something with people, you can often share the individual things of interest instead. But it depends what you want to share.
But they are a) very old - not sure if things have changed or been added, and b) I am not sure which of the locations mentioned there correspond to what section of the export process (exported config file).
As to that exported config file, I might be ignorant about the tech but in notepad it is mostly random symbols....
Post Scriptum: My configuration doesn't have anything personal, it's the way I would configure it for any random Windows user who wants to move to DOpus asked me to configure it so they will get along with it well and with an easy learning curve. (I looked carefully at every single config option and read up on it if I was not 100% sure, which most people don't do (plus many years of usage). I just don't know if it will also export any personal stuff in some corner of the config data.