1 and 2 keys to change tabs in Safari (like in Opera)
You wouldn't make the shortcut from keyboard preferences. I believe that you would add this shortcut from Automator however I am not on my computer right now so I think that will work but I haven't tested this specific shortcut. If that dosent work then there is always the option of "⌘+`/⌘+Shift+' " to go to the next or previous tab. Hope this helps!