(The size of the block is 5 mm or 0.5 cm, not 0.5 mm; I'm sure you know that and it was just a typing error)
You're not supposed to cram your letters into that 5 mm space: you generally use two lines, which gives you a 1 cm lineheight.
That being said, I don't like that raster size for writing. They're nice for drawing schematics and stuff, but for writing I very much prefer a grid of 4mm × 8mm (like this: https://www.dbs.be/images/vergroot/2518_2.jpg).
You're not supposed to cram your letters into that 5 mm space: you generally use two lines, which gives you a 1 cm lineheight.
That being said, I don't like that raster size for writing. They're nice for drawing schematics and stuff, but for writing I very much prefer a grid of 4mm × 8mm (like this: https://www.dbs.be/images/vergroot/2518_2.jpg).