Creating axes with fixed distance from figure edge

Hi everyone,

I am interested in creating axes in an interactive figure where the
distance from the spines of the axes to the figure edge are constant
in absolute terms.

To clarify what I mean, when using add_axes([0.1, 0.1, 0.8, 0.8]), the
spines of the axes are always located a distance from the edge of the
figure that is 10% of the size of the figure. However, in my case,
since the font size is constant, I want to be able to say that the
spines should always be e.g. 0.5" from the edge of the figure, which
would avoid wasting space when making the figure larger.

Is there a way to do this currently?

(I am aware of set_tight_layout which would result in something
similar, but this is not what I am after - I would like to be able to
specify the exact absolute distance from the figure edge)