Cosmologist Sean Carroll, the author of a highly recommended site and podcast is a self-described "mad-dog everettian" and a consummate Bayesian, repeatedly cautions against worrying about other branches that separated in the past when making decisions in the present. He is a really smart fellow and has spent a chunk of the last three years interviewing other really smart scientists of various disciplines, and is likely worth listening to, though not necessarily agreeing wholesale. He is also very much more pro-philosophy than an average physicist:

in exactly the areas of physics that I care about, in cosmology and in quantum gravity and fundamental physics, there are questions that philosophers understand at least as well, if not better than physicists do.

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How do you reason anthropic-ally in large universes, what is the nature of the arrow of time and causality and locality, what are the issues and potential solutions to problems of the foundations of quantum mechanics or statistical mechanics? These are areas where philosophers have thought deeply about them and physicists tend to gloss over them, ’cause that’s what philosophers do, they think deeply. Now, they’re not that great at coming up with solutions, because they’re philosophers, they’re not scientists. It’s not their job to come up with solutions. The philosophers are really, really good at diagnosing the problems, they’re much better than the physicists are. Physicists are good at ignoring problems when they’re not absolutely necessary for them to be confronted.

But philosophers know that these problems are there, and they try to categorise what all the different possible approaches are, etcetera. And what would really be great is if physicists and philosophers really worked together at these intersection regions. And the truth is that they don’t. There’s a little bit of overlap. There’s some good counter examples to this wild generalisation I’m pushing right here, especially in Quantum Mechanics, that’s the one area of physics/philosophy overlap where there are really both physicists and philosophers who talk about it, but it’s not as if every physicist who does Quantum Mechanics has any idea of what the philosophers are talking about, and they could. I recently saw a paper that surveyed the opinions of physicists on the foundations of quantum mechanics, and it’s just embarrassing how little factually physicists know about the different approaches, whether it’s Copenhagen or Hidden Variables, or many-worlds or whatever, there’s just very, very basic mistakes that physicists make ’cause they don’t know what’s going on.

Some of them know they don’t know what’s going on, like there’s a substantial number of people who say, “I don’t know,” but there were too many people who thought they knew, and was wrong. And philosophers, likewise, philosophers have their own workshops, conferences, what have you, and don’t always talk to physicists. And so as a result of that, the questions that are within the domain of foundations of physics, like I mentioned, naturalness, entropic, etcetera, are not necessarily the ones that philosophers are training their keen minds upon, because they don’t move around as quickly as the physicists do, jumping from topic to topic. So they all have their favorite problems and they’ll think of them for a very long time. There’s plenty of room for improvement in the interaction between physicists and philosophers.

The decision-theoretical question you are asking it likely to be one of those, and, odds are, not caring about MW branches that split long ago is a very reasonable approach.

What's MWI and what's abortion?