After confirming the tapeout (by clicking the submitter confirmed link), if I want to update the application to the latest tapeout result do I need to do anything? change to unconfirmed and back again?

You can run precheck & tapeout even in the confirmed state.

So the final application will always use the last tapeout?

yes, if you have multiple

successful

tapeouts, only the last one ran prior to the deadline is taken into consideration. @User, please confirm

confirmed. thx.