How can I resize the volume OSD in Gnome3 (Shell)?

How can I resize the volume OSD display to a more "sane" size? Currently it takes about 1/4th of my screen height. I may be shortsighted, but not that shortsighted.

I checked my theme settings, but couldn't find any hint for setting the size of this window. Where do I have to look?

Is it even a theme issue or is it gnome globally?

Solution 1:

I could not find an extension, so I built one that let the user determine size, position and delay for the OSD window: https://extensions.gnome.org/extension/1345/better-osd/

Source code: https://github.com/hajdbo/Better-OSD-GNOME-Extension/blob/master/README.md