Well, I don't think that this experiment would work at all. (Even with the assumption that many worlds is correct).
A radioactive decay occurs/doesn't occur. It is detected by a quantum amplifier and the universe gets split in two. In one of those universes the amplifier clicks, in the other one it doesn't.
"You" are in one or the other of these universes. A few moments later you get shot in the head and die. It will surely be of little consolation to your carcas breathing its last breath that somewhere else there is some "other you" that is enjoying a great stream of luck, while you are lying here bleeding.
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