Just a note on removing margins with the Modify Epub plugin: Normally if you have the left/right margins set in body then the plugin will remove/change them to match your preferred settings in Calibre. But it doesn't seem to be able to remove margins that are part of a CSS class, only directly from a body {} statement. This means it doesn't remove margins for Calibre created/converted books, because calibre uses a class for everything.
e.g. Modify Epub will work fine if the book has a statement like this in the stylesheet:
Code:
body {margin-left:5pt;margin-right:5pt}
But if it has a class in the stylesheet like this:
Code:
.calibre1 {margin-left:5pt;margin-right:5pt}
and the HTML usues it to set the margins as in:
Code:
<body class="calibre1">
then Modify Epub won't work for those margins.