Originally Posted by wass
Another problem is the "non-justified text".
The PRST1 will honour whatever css is in each particular epub. If the css inside the epub specifies text-align:left
you will get a ragged right edge, as in your pic. If it specifies text-align:justify
it will be justified right&left. Playing with the fonts shouldn't have any effect on justification.
If your epub is non-DRM you can use Calibre or Sigil or edit manually to change the css to suit.
The margins can be changed similarly.