Looking For Voiceover-Compatible Toastmaster Timer App

Hi,

I'm a member of a local Toastmasters club. In case you're not familiar with Toastmasters, it is a worldwide organization to help improve public speaking skills. One role I have difficulty performing is that of the Timer. When I've done it in the past, I've used the Stopwatch feature in iOS's Clock app. That's fine for timing a speech during a contest, but not so much (I don't think anyway) for things like Table Topics, where normally there would be different indicators for one minute, 1.5 minutes, then two minutes as an example.
Regular speeches are also timed like this.
There are many Toastmasters timer apps in the App Store, but I'm wondering if anyone knows of one that works great with Voiceover, and that could be customized to use either sounds or vibrations as indicators for how much time is left to speak?

Thanks.

Yours Sincerely,
Kelly Sapergia