I'm not saying commitments aren't useful, I'm just not sure how you can make them. How do you prevent your future self from reasoning their way out of them?

People don't normally do things because that would be the rational thing to do. They do things because they believe to be the kind of person who does such things. Usually you would have to train to overcome that bias, but in this case you can make it work in your favor. So here is the three step program to learn to precommit:

1. convince yourself rationally that being able to precommit has a great expected utility and that hacking yourself to be able to precommit is a good thing.
2. Make lots of small easy to follow precommitments like precommiting what to have for lunch, etc. But always be sure to doublecheck that you will actually be able to do it and won't be inconvenienced by it. When it is time to follow through on them remember you're not doing it for the precommitments but for a "higher good".
3. When you have followed on a precommitment tell yourself aloud: "I am the kind of person who always follows through on precommitments."

That should make precommitments second nature to you.