Yeah...there's no way on Earth you crack the headstock all the way off to reglue. That's highboy talk. I have a Bigsby '72 deluxe with the very same neck crack but repaired with glue injection. The luthier picked it up just BY THE HEADSTOCK, upside down, to show me the repair would hold. And it did. Great guitar, for real.
Sometimes, depending on the crack, it isn't possible to get glue to all the recesses of the crack through injection. If the glue doesn't hold with the injection breaking would be the next step. It is also a possibility the headstock can break while flexing the crack to inject glue.
