I feed my hatchlings baby mealworms, and also the ones that are white since they are fresh shed mealies and easier for the baby leo to digest. I breed my own mealworms so I have every size available.
With crickets I feed them either 1/8 in. or 3/16 in. crickets. The 1/4 might be a little big, but I haven't tried it. My 2 month old baby gecko is eating 3/4 in crickets already and doesn't seem like she has a problem. In my opinion I'd at least wait until the gecko is a month old before trying 1/4. You wouldn't want it to choke on a cricket. Your only suppose to feed them prey items no bigger than their head.
Hope this helps
~Shayna~
Leo Lovers Lizard Lounge