Heh, I made something just like it, https://slitdecision.com/
Disclaimer: I have no background in physics at all. I saw this universe splitter and read "Anxiety is the Dizziness of Freedom" (Science-Fiction novella by Ted Chiang - the one mentioned in here), and thought hey that's fun.
Nice one! Back in 2012 I built the (now defunct) Freakonomics Experiments site[^1] that used had the same A vs. B premise using John Walker's HotBits[^2] from Switzerland.
In case of interest, Steven Levitt published their - albeit single-Universal - findings in "Heads or Tails: The Impact of a Coin Toss on Major Life Decisions and Subsequent Happiness"[^3]
[1]: https://www.freakonomicsexperiments.com/home/faqs/
[2]: https://www.fourmilab.ch/hotbits/how3.html
[3]: https://academic.oup.com/restud/advance-article/doi/10.1093/...