We've been feeding daily, and dusting each feeding. The crickets we can get locally from Petsmart tend to vary widely in size - the "small to medium" can be anywhere from 1/4" to 5/8" it seems. We feed 4 crickets per frog but I've told my son (who does the actual feeding most nights) to "double up" the wee crickets, i.e. feed an extra for every tiny cricket there is. I'm not really sure how big the crickets should be for these frogs but I know the "medium to large" variety that Petsmart has goes all the way up to adults which look enormous. The frogs are about 3 inches from nose to rear end.
Here is "Cody," waiting for his dinner:
The other frog ("Viper" - my son named them ;P) seems to be a bit plumper than Cody.
Oh, and we have two glass bowls in the enclosure like the one you see Cody in. Each feeding my son puts a frog in each bowl before feeding them - if they are not already waiting for him! They do eat eagerly, in fact they eat right from his fingers much of the time. I suppose I should also mention that I haven't been able to get a glass cover for the terrarium yet, and the humidity does tend to drop to about 30% except for right after I spray.