These commands will do the trick. You can comment out (by beginning the line with a "#" sign) any of the four orientations you don't plan to use, and you can edit the names in the second column ("Portrait," "> Landscape" -- meaning with the thick edge on the right; "< Landscape" -- meaning with the thick edge on the left; and "Upside Down") to whatever you wish.
Code:
# -----------------------------------------------------------------------
menu_item :main :Portrait :nickel_orientation :portrait
menu_item :main :> Landscape :nickel_orientation :landscape
menu_item :main :< Landscape :nickel_orientation :inverted_landscape
menu_item :main :Upside Down :nickel_orientation :inverted_portrait
# -----------------------------------------------------------------------
menu_item :reader :Portrait :nickel_orientation :portrait
menu_item :reader :> Landscape :nickel_orientation :landscape
menu_item :reader :< Landscape :nickel_orientation :inverted_landscape
menu_item :reader :Upside Down :nickel_orientation :inverted_portrait
# -----------------------------------------------------------------------
menu_item :library :Portrait :nickel_orientation :portrait
menu_item :library :> Landscape :nickel_orientation :landscape
menu_item :library :< Landscape :nickel_orientation :inverted_landscape
menu_item :library :Upside Down :nickel_orientation :inverted_portrait
# --------------------------------------------------------------------------