This is a layout offering 1 hold for every 2 square feet which is industry standard for Middle School aged children up to adults.
If you have Elementary aged children, add 4 more medium holds per panel.
If you have toddlers (under the age of 5), add 8 more medium holds per panel. The logic behind this advice is that you don't need larger holds to make the wall easier, you need the holds to be closer together so the little ones can reach between the spaces of holds.
