How to allow 1/3 -> 1/2 -> 2/3 cycle?

[mankoff]

How can I set up an option to cycle through 1/3, 1/2, and 2/3 of monitor width?

I can cycle through 25, 50, and 75 % width with:

{
  "default": {
    "minwidth": 0.25,
    "maxwidth": 0.75,
    "xdivs": 4,
}

But I'd prefer 1/3, 1/2, and 2/3. I can't get that to work. If I set min/max/xdivs to 0.33/0.67/4, it locks at 50 % (1/2). If I set min/max/xdivs to 0.33/0.67/3, then it lets me do 1/3 and 2/3, but not 1/2.

This could be simplified if rather than doing min/max/div I could just specify I want 0.33, 0.5, and 0.67.

Full config is:

{
  "default": {
    "minwidth": 0.25,
    "maxwidth": 0.75,
    "minheight": 0.33,
    "maxheight": 0.67,
    "padding": [
      0,
      0,
      0,
      0
    ],
    "snaptocursor": false,
    "spacing": 0,
    "xdivs": 4,
    "ydivs": 2
  },
  "keys": {
      "accelerator": "<Mod4>",
      "commands": {
	  "Left": "left",
	  "Right": "right",
	  "Up": "top",
	  "Down": "bottom",
	  "m": "maximize",
	  "g": "topleft",
	  "r": "topright",
	  "h": "bottomleft",
	  "n": "bottomright",
	  "KP_4": "middle",
	  "Tab": "cycle-monitor"
    }
  }
}