A third way of looking at this thought experiment would be through the lens of value uncertainty. Through this lens, it does make sense to pick option one. Even if you have a thousand times more credence in the theory that happiness is the arbiter of value, the fact that no happiness is created either way leaves the door open for your tiny credence that beauty might be the arbiter of value. Value uncertainty suggests that you take the first option, just in case.
This summarises my view. Might as well choose first option just in case.