That’s an interesting way of doing it.
The meta keys shouldn’t change, although I can’t guarantee that. It would be mentioned in the changelog if they did, but I don’t see that happening any time soon.
Personally, I would just build the page header in GP Hooks so it applied to all pages.
The best way to do that would be to build it on a page using the settings you want, then copy the HTML generated and the CSS generated.
Then add that HTML into GP Hooks, and add the CSS to your child theme or CSS plugin.
Let me know if that makes sense or not 🙂