best way to display numbers with a led matrice

Think about it. Character LCD, Graphic LCD, Graphic TFT, Graphic OLED or even LED matrix all involve fairly low resolution fonts. e.g. 7x5

7x5 works quite well. 8x8 looks pretty horrible. If you want to "improve" a 7x5, you add descenders. Thickening random parts of a letter does not work well.

Since you are limited to 8 rows of LEDs, your second example is more effective. (in my personal opinion)

David.