I have a blocking stutter, too. I've done about a hundred presentations. Some went my way, and some didn't. I don't have any novel solution for you, but I can share insight. For some of the ones that didn't go my way, I didn't get a lot of sleep prior and/or was not entirely confident about the content. Some tricks that help me are acting somewhat of a character, singing my words, even if slightly, and deep breathing while taking my time. Not caring also helps but is more complex to achieve. Good luck!