960.sketch
Because I love working with my 10px*10px grid, and Sketch doesn't allow to have both "square" and "layout" grids activated, I made this little Sketch file.
It's a template file of a classic 960 pixels wide grid with 12 columns for Sketch app. So you can keep the "square" grid settings on, and show the columns with guides or layers.
It's centered for a 1440px viewport and contains layers group & guides (Ctrl+R).
Hope it helps !