Not "I shout the loudest about it".
And "weakly held" meant "I am willing to believe there's data out there showing I'm wrong, and I will look at any new data with an open mind". Not "I'll flip if somebody shouts louder".
And sure, on the face of it, the proposed solution here addresses that, but... we don't know "how sure" we are of something. It's a made up number. And I'm willing to take bets that the same people who do the loud shouting will be the ones who just declare every certainty 100%. (The smarter ones will pick 98%).
The key to making this work is openness to new data.
If you want a rhetorical trick to facilitate debate, I prefer the old "Tell me what I'm missing" - it presupposes you don't have all the data, nudging you to be open to counterpoints and validating people who might want to offer counterpoints.