All of this is such a matter of choice.. You can use two initials , 3 initials , 3 initials with the last name initial larger in the middle, and I really like the single last name initial. It really makes a statement. For very young pre school children, you can use the Stacked look with large initial and name below. once the kids are school age, use names wisely as for safety reasons. Have fun!!
My choice is to put the initial with the name on top of it. But only my thoughts. Hugs, Judy