Yes, it is possible to over feed, though that's more likely when full grown than while still growing. Keep an eye on the fat pads on the head and the shape of the tai, and weight him occassionally.
He could eat 8 plus crickets a day, I was originally told to feed him 4 crickets a day and i'll put 4 in the morning but he seems to be searching for food around halfway through the day so i put a couple more in and he'll go right after them, i'd just hate to over do it.
Also each of the crickets are powdered with calcium with no vit. d3 each day plus with a multivitamin and calcium with vit d3 on alternating sundays besides having the crickets gut loaded with fruits and veggies.