One of the reasons I'm still using my Zodiac for reading is that no matter
how I hold it, there are always paging buttons in easy reach of either hand. Consequently there is never any problem finding a comfortable position for reading in bed.

I'm most likely to page forward and back with my left thumb on the joystick if holding the device in my left hand, with my right thumb on the right shoulder trigger (to page forward) and hard buttons (to page back) if holding it in my right hand, or with left and right forefingers on the shoulder triggers if using both hands.