I've updated the `Compact homescreen layout (Glo only)` patch in post #2, I reduced the margins even more and also reduced the spacing between tiles, so now it is possible (only just) to squeeze in three rows of book tiles.
(Edit: Updated the patch again to reduce the size of the % read font, which was making tiles for partially read books a bit larger than the tiles for new or finished books.)
This patch will probably only work on the Glo, as the Aura has a slightly shorter screen.
See
this post for how my Glo's homescreen looks without the patch. Attached is a screenshot with the patch: