I was actually going off the idea that the vast majority - 100% minus pr(survive all suicides) - of worlds would have the subject dead at some point, so all those worlds would not be convinced. Sure, people in your branch might believe you, but in (100 - 9.3x10^-302) percent of the branches, you aren't there to prove that quantum suicide works. This means, I think, that the chance of you existing to prove that quantum suicide proves MWI to the rest of the world, the chance is equal to the chance of you surviving in a nonMWI universe.

I was going to say well, if you had a test with a 1% chance of confirming X and a 99% chance of disconfirming X, and you ran it a thousand times and made sure you presented only the confirmations, you would be laughed at to suggest that X is confirmed - but it is MWI that predicts every quantum event comes out every result, so only under MWI could you run the test a thousand times - so that would indeed be pretty convincing evidence that MWI is true.

Also: I only have a passing familiarity with Robin's mangled worlds, but at the power of negative three hundred, it feels like a small enough 'world' to get absorbed into the mass of worlds where it works a few times and then they actually do die.