Default (OSX).sublime-keymap

[
    {
        "keys": ["super+alt+shift+5"],
        "command": "set_layout",
        "caption" : "1-2 Grid",
        "args":
        {
            "cols": [0.0, 0.5, 1.0],
            "rows": [0.0, 0.5, 1.0],
            "cells":
            [
                [0, 0, 1, 2], [1, 0, 2, 1],
                              [1, 1, 2, 2]
            ]
        }
    }
]

Main.sublime-menu

[{
"id": "view",
"children": [{
    "id": "layout",
    "children": [{
        "command": "set_layout",
        "caption" : "2 Columnas / 1 Fila",
        "keys": ["super+alt+shift+5"],
        "args":
        {
            "cols": [0.0, 0.5, 1.0],
            "rows": [0.0, 0.5, 1.0],
            "cells":
            [
                [0, 0, 1, 2], [1, 0, 2, 1],
                              [1, 1, 2, 2]
            ]
        }
    }]
}]}]