Poor prior work is not ideal for a solid new repair OR gaining experience with headstock repairs in general. We will at times turn away headstock breaks because the last person who took it on essentially destroyed the instrument with poor..... prior.... work.
It's much easier to take a fresh/new break that has been unadulterated by anyone's perhaps poor choice of glue and lack of knowledge about these breaks, glue, clamping, etc.
There are exceptions where it breaks somewhere else the next time and the original repair is sound and then it's something that we will take a look at and maybe take it in. But in general someone who calls us and tells us that a prior headstock repair break and repair has again failed will hear from us on the phone that their expectations should be set pretty low for if we take it on but we are willing to take a look if they are willing to bring it in.
None of this is to say that it can't be fixed. But all of this is to say that it may result in major scope creep and a much larger, more involved job with more finish touch-up than meets the eye. It's not fun work either and can be a long slog....
Some guitar repairs are like that dime sized spot that looked easy to sand out and when you are done you have a softball sized spot that does not match.... They are to be avoided if you guarantee your work, value your time and pay your bills.... A commercial perspective for you Snow;)
Nonetheless you will receive lots of suggestions even when no one including me has had any opportunity to see what we are even speaking of.... I would proceed with caution and also ask yourself if you want a wounded Hummingbird or want to have to flip it to recover what may end up being a massive personal investment.
This reminds me to put my feeders out in a few weeks my Hummers are usually here May 15th and hungry too.