I personally don't use or recommend any type of sand for a dragon enclosure. Its always an impaction risk. The amount of crickets used will depend on the size of the crickets as well as the size of the lizard. But baby dragons eat a lot of crickets. And keep in mind that the total lifespan of the crickets are 8 weeks so they grow fast. If you order in bulk, order a bit smaller than what you need or they will quickly grow larger than your dragon can eat. And breeding crickets is a hassle! I much prefer the dubias and mealworms!