I would contend that it should be possible to find an implication of each interpretation that only exists in that interpretation. If, for example, Many Worlds is true, then it necessitates that any sort of information cannot be destroyed and vice versa, when considering the system as a whole. If Many Worlds is false, then superposition information is lost when superposition collapses, you cannot recover from the collapsed wave a complete set of all superposition states that existed. I'm sure that someone will point out that superposition isn't information in some specific sense, but that is the whole point. Many Worlds is impossible if you can show that superposition ISN'T the sort of information that IS conserved, because Many Worlds requires, by its very nature, that it is.
This gives us a test that does not require us to look into other universes and can be done purely by theoreticians. If you regard the system as a 5D system, then is that information conserved or not? Yes or no. If yes, then that does not "prove" Many Worlds, but it does mean that only interpretations that preserve that information in some form are viable. If no, then Many Worlds, and all other interpretations that preserve that information in some form, are ergo impossible. Instead of filling out questionaires on what you think is likely, try to prove that it can't be possible and see if you succeed.
I would also argue that physicists thought that the Lorenz contraction was a neat bit of maths by mathematicians that had nothing to do with reality, until Einstein cottoned onto the fact that it actually did. You cannot trust physicists who have an innate dislike of mathematics. This doesn't mean that maths always represents reality, but it does mean that it does so unreasonably often and unreasonably well.