Everything is finished. Not sure if I am allowed to put a link yet, so I'll wait on that.
HUD Customization with boss font and the health bar image.

You can toggle double HUD mode if it's available
Default image is changed:

Works for double bosses (if the toggle is enabled)

Also has support for a couple types of invincibility, which just turns the bar almost black

I also fixed how the HUD positions, so it should work better on most resolutions.