I really like the main functionality of Cmd+# to switch tabs. But for the Cmd+Shift+T feature to open a closed tab, there is a much better extension: https://github.com/Antrikshy/RecoverTabs
SafariTabSwitching overrides this and I cannot make it not to.
RecoverTabs remembers tabs and allows reopening of more than 1.
To get Cmd+Shift+T working just as Cmd+Z, users could add that shortcut themselves in Preferences.
I tried to install the release before Cmd+Shift+T was added, but it did not support Safari 8.