When the viewer fits into approximately half of the available space, the padding takes more than 10% of the viewer window. Since it doesn't scale with the viewer it's impossible to use the small ones.
I'd be happy to contribute by making either tweakable parameters for paddings or by setting more sane defaults. At least if no one else considers this a problem, I want to change my local settings.
I tried to search through the code quickly, but since Glueviz is a large project I haven't found an entry point, so I need some advice or assistance in contribution.
One place to start is here: http://docs.glueviz.org/en/stable/customizing_guide/custom_viewer.html#other-guidelines which shows you how to override the axis padding margins like:
axes.resizer.margins = [0.75, 0.25, 0.5, 0.25]