Not sure if you would be interested, but I broke taffybar's strut support out into its own (gi-gtk based) repository. You can find it here:
https://github.com/IvanMalison/gtk-strut
It's a small thing, but it might be nice to share work on this somewhat tricky portion of setting up the window. I will likely fix taffybar/taffybar#264 soon, which is something this library could also benefit from.