Just overwrite the entire variable with your own. For example, if the Bartender4 saved variable is called Bartender4DB (look in its TOC file) then you would just do:
Code:
Bartender4DB = {
-- your table contents here, copied from your saved variables file
}
ReloadUI()
Note that you
cannot do this before Bartender4 has loaded. You should wait until the PLAYER_LOGIN event fires. Also, you cannot reload the UI without user interaction, so the whole thing should be tied to a prompt, eg. "This looks like your first time loading SuperAwesomeUI. Would you like to apply all the settings and reload your UI? Yes/No".
If you need some examples, go look at some UI packs that already do this, such as
Mayron UI.