you can zoom the boox display 125/150/175/200/300/400 percent to page or to height or to width with single column as well.
just set the font to small then choose zooming from the menu and try the different options. Im sure one will work for you and the best part is its persistent. So once you set it for that book you dont have to again it.
here is the DR800 manual using fit to width zooming in portrait and landscape