I have two area charts. One is above the other on the page.

I want to keep their respective y-axis lined up with one another but I
cannot figure out how to do this.

The data that the charts show is unknown to me and can change so I
can't just set the fonts on the axis because at times the labels on the
y axis may be a single digit and at other times it may be three or
more.

Is there any ways to set the size allowed for axis labels in pixels or
some other measurement?

Any help would be appreciated.

James