It is up to you how many grids you want to put. You can put 2 grids or even 99 grids as long as the minimum is filled.
The grid will be placed in 2 behaviour which you can choose, arithmatic order or geometric order. As the name implies, arithmetic will give you fixed gap between grids, meanwhile geometric will give you fixed percentage gap between grids. For example 100-200, arithmetic will put order on 100,120,140,…200. Meanwhile geometric will put 100,120,144,…. (every 20% gap)