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.

Well, I tried to understand some double-slit corner-cases. If I read some classical Copenhagen-approach quantum physics textbook, it is hard to describe what happens if you install a non-precise particle detector securely protected from experimenter's attempts to ever read it.

Of course, in some cases Penrose model and MWI are hard to distinguish, because gravitons are hard to screen off and can cause entanglement over large distances.