There's a long time Moderator and engineer on the Muzzle Loading Forum named Zonie.
He's a relative expert on the technical aspects involving threads and drilling & tapping nipple holes and such.
He posted in 2019 about a similar question and said,
"Since the major diameter of the threaded hole is only .015 smaller than a 5/16 thread, there isn't enough material to thread the existing hole for a 5/16-24 threaded nipple. That is the next larger size standard nipple thread and it is used on percussion muskets."
And that's why when Green Mountain and TC repairs similar threading errors, they use helicoils to repair the hole and restore the original thread.
After all, they're concerned with safety and long term reliability.
And that was the subject of his post and the thread, about having GM install a new helicoil on an old defective factory helicoil installation.
His post also describes how to install a new helicoil. --->>>
https://www.muzzleloadingforum.com/threads/is-this-a-helicoil.116588/
Anyway, what I'm driving at is that no one knows how badly your threads are damaged and worn.
While someone may get by with 1 or 2 taps to repair their problem, TOW and Zonie seem to be saying that with such a small tolerance of remaining metal available to do the job in a satisfactory way, all 3 taps should be used.
That's because no one can tell you otherwise since they don't know.
But they can say that to satisfy safety concerns, that you should use all 3 taps.
If TOW will sell you all 3 taps plus 3 nipples for you to attempt your repair, and then you can return the taps and nipples that you haven't used, then that could be
an option.
However, if you don't do it that way, then you're going to be stuck with 3 shipping charges to keep ordering taps for a simple 2 or 3 tap job.
And even then, you should consider yourself lucky if you don't need to install a helicoil.
That's the best advice that I can think of to protect yourself.
Order all 3 taps and nipples with the understanding that you can return some unopened. and/or unused.
But short of that, I would buy them with the plan to use all 3 hoping for the best.
Why guess that you won't need extra taps when you do need them until you can prove that you don't.
Having a nipple blow out with 100 grains of powder is not a joke.
The nipple is basically getting similar pressure put on it as a breech plug.
Don't you agree that it better to be safe than sorry, and you want to avoid extra shipping charges if possible because it's all going to cost about the same in the end anyway.