as far as I am aware the only way to change those bindings is by modifying some python files. those number are being assigned to the menu automatically in base of the order the calls are made. it kind of doesn't make too much sense but there is a specific order in which are assign. the first 4 calls will always be the S,W,E,N points and so on.
so in order have your favorite menus calls with the keybindings you like, you need to change the order of the lines.
added some duplicate lines that creates number 7 and 9
If there is another way I am not aware.. you better of learning how to do your pie menu and use that IMO.
the file in question of the
Z pie menu in Blender 2.80 is
space_view3d.py. you can find it in blender configuration inside the script/startup/bl_ui folder.
mac path will be
I am not on windows right now but that will be something like
C:\\Program Files\Blender Foundation\Blender\2.79\scripts\startup\bl_ui\space_view3d.py