Keeping cells square
The generator uses one millimetre step on both axes. Landscape does not turn squares into rectangles; it only changes how many cells fit. After printing at 100%, ten 5 mm cells should measure about 50 mm horizontally and 50 mm vertically. If only one axis matches, the printer scaled the page nonuniformly.
Major lines every five cells mark 25 mm blocks on a 5 mm grid. Load Fine 2 mm, Standard 5 mm, Large 10 mm, or Major-Line Graph Paper from the template catalog. Printing notes: print at the intended size.