You might want to make the base font a little larger. Although the font does scale (very nice) when the font size setting is changed, the font itself is smaller than that in the settings option. To say another way, my font selection is set to Medium. When I look at the size of Medium displayed in settings, it is larger than what DoDroid displays as a medium font. Therefore, if a user wanted the font to be larger they would have to change the font for the entire system in settings. If you want to keep the font scaling the same, you may want to consider allowing the user to change the font size (like in Kindle app).
You might want to make the base font a little larger. Although the font does scale (very nice) when the font size setting is changed, the font itself is smaller than that in the settings option. To say another way, my font selection is set to Medium. When I look at the size of Medium displayed in settings, it is larger than what DoDroid displays as a medium font. Therefore, if a user wanted the font to be larger they would have to change the font for the entire system in settings. If you want to keep the font scaling the same, you may want to consider allowing the user to change the font size (like in Kindle app).