I was using aterm as a popup message box on another project
and decided I was not content with the default font size.
I wrote a small script to created sample terminals with different
fixed width font sizes.
This is the command to retrieve that list of fonts:
tc@E310:~$ xlsfonts | grep -E "[0-9]x[0-9]" | sort -u | sort -g
5x7
5x8
6x10
6x12
6x13
6x13bold
6x9
7x13
7x13bold
7x14
7x14bold
8x13
8x13bold
8x16
9x15
9x15bold
10x20
12x24In case anyone is wondering why I called sort twice, it's because
when I combined the -u and -g options, the bold versions of the
fonts no longer showed up in the list.
The script launches a 2 line by 60 character aterm instance for
each font. Each terminal has 2 lines of text.
The titlebar lists the font size.
The terminals are on the right edge of the screen.
Each terminal is shifted down 50 pixels from the previous terminal.
The result looks like this:

Near as I can tell, the default font size is 6x13.
I found the 7x13 size easier on my eyes.
A copy of the script is attached to this post.