Positions relative to certain common points can be set:
No attempt is made to take account of the page rotation, so you might like to use -upright (see upright) first.
The -shorter-side modifier can be used to indicate that all the positions above are relative to the shorter side of the page, any rotation required being automatic. In other words, top, topleft, topright are either on the top or left, depending upon which is the shorter side, and bottom, bottomleft, bottomright are either on the bottom or right similarly.