The little I tried with the Tern, it seems that customization is limited to one field only (we set the display to "Big", don't know if there is more space with smaller fonts)
I did not mention, but we both use reading lenses and both computers were also ok to read without them.
If you can read the Tern without special lenses, and you ARE using special lenses, why would you set the Tern to "Big" mode?