Since the application is stuck in Internet Explorer 7 land at the moment, you definitely need me to create these things. In the future, it might be possible to do much of this on your own.
FYI, I updated the <timer> token and added an attribute percentage, which takes a formula. So it's possible to do this, for example:
<timer percentage="(secondsLeft % 6) / 5">
Which causes the timer chart to count down the last 5 seconds. Actually in this example it goes from 100% circle to gone every 5 seconds, but if this was in a property set that displayed only during the final 5 seconds, I think it would do what you want.