My new Veiled Charm eats some where from 6-8 crickets a day along with 1-2 waxworms depending om how meny crickets he had that day... and he is 6 months old so... there is a few pics of him on my profile so mabe you can compair to more figur out his age.
You would be fine with just crickets, but better with a variety by adding in some Supers, Silks, etc. If you were feeding just crickets depending on size he could eat from 6-12 medium crickets daily at this age.
