I would skip the halyard. I do it this way:
1) Loosen and then disconnect the uppers.
2) Rebed their chainplates.
3) Wait until the bedding cures (if you are using bedding that cures).
4) Reattach and tighten the uppers5) Loosen the lowers
6) Rebed their chainplates
7) Wait until the bedding cures (if you are using bedding that cures).
8) Reattach and tighten the lowers
You can do them all in 3 days (assuming a 24 hour cures). The stays + uppers is far more than what you need to support the mast at your slip. The same is true for stays + lowers.
Well, I am planning to use 3M101, which is what I've used before. Can't use butyl tape here because my chainplate covers are not through-bolted, so polysulfide is my preference. It cures over several weeks.
So my assumption was that I could just rebed one at a time, and put everything back together without waiting, since there's really no way to take the boat out of commission for weeks anyway.
Not sure I like the idea of loosening both sides without halyard reinforcement...makes me nervous, even if it does make sense.