When I first tried to breed them, I used soil and ran into the same problems as you. Keeping them warm made the soil dry out within a day or two and then they would never hatch out. After my baby dragons hatched, I would put the used vermiculite in coffee cans to store it for potting plants later. It stays moist long enough to hatch baby dragons in 60 days, so I decided to try it with the crickets. It did start to dry out a little half way through the incubation, but if I dampened it a litttle bit before it got completely dry, they would always hatch out successfully within 10 to 14 days. I noticed the hotter it was, the faster they hatched, so I put the containers of eggs in my garage where its humid here in Florida, and stays about 95 to 100 degrees through the day. Some of them hatched in as little as 1 week, never more than 10 days. And trust me, I tried unsuccessfully for a year before I tried the vermiculite.