Ah I understand!
That wasn't possible, but I have created a beta version that adds a feature which enables this layout (and even more complex layouts too).
Cycling Window Manager 1.1.0 beta 1 Macros.kmmacros (174 KB)
Use the new compound hotkey ⌃⌥⌘[] to use the current window to define a sub-region to tile within. Both ⌃⌥⌘[ and ⌃⌥⌘] reset the tiling area to the full front-most screen's area. It also resets automatically after 40 seconds.
Now, you should be able to create sixths or even more complex layouts! For sixths, you would first tile a window to be in one-third of the screen. Then, set that third as the tiling region by pressing ⌃⌥⌘[]. Now you can use ⌃⌥⌘↑ or ⌃⌥⌘↓ to tile within the chosen third of the screen, thereby giving you sixths.
Let me know what you think! I still have some issues to work out around the nuances of when the tiling area should be reset. But, I think this beta version should be a good start.
The cycling window manager only supports navigating external screens. Other community members have made macros for navigating between spaces: MACROS: Desktop Spaces • Macros to Improve Navigation and Window Management, v4.0