I use this layout for both my Planck and Levinson. I also have a very similar keymap for my Preonic.
Check out my userspace for the custom keycodes that are used in keymap.c.
At a very high level I use 4 layers:
make planck/rev5:mguterl:flash # For Planck rev5 or earlier and Planck Light
make planck/rev6:mguterl:flash # For Planck rev6
make keebio/levinson/rev2:mguterl:dfu # For Levinson rev2