Hmm. I'm also pretty sure that the double-slit experiments are not evidence of MWI vs. waveform collapse.
They are evidence against wave-form collapse, in that they give a lower bound as to when it must occur. Since, if it does exist, it's fairly likely that waveform collapse happens at a really extreme point, there's really only a fairly small amount of evidence you can get against waveform collapse without something that disproves MWI too. The reason MWI is more likely is Occam's razor, not evidence.
From Costanza's original thread (entire text):
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