How many crickets should he eat in a day. I let the fruit cup in the vivarium at all times (replenishing it with about 1/4 tsp. daily) Spotted Dick eats about 2 crickets, 1/8 tsp fruit daily and 1 or 2 flies. Do you think that is too much???
While growing grandis do tolerate an excess of food quite well, I prefer to stay on the lower side. That assures proper bone growth and inner organ development in the absence of excess fat bodies.
In praxis that means that I do feed juvenile grandis twice a week maximum and not more than the insect equivalent of 6 crickets a week. Fruit and repashy are fine as well, but are given only once a week in small amounts.
Anyhow, as I said, grandis are quite robust and will grow up properly in most cases even in the presence of an excess of food. But if you want a long living animal, its safer to feed less.
Best regards
Ingo