Good info. I would be reasonably sure that anyone that has hatched Dry eggs will tell you that there is some bulging at the bottom of the eggs. I suspect that is because the substrate is moister that the air above the eggs and the shells stay more supple. This will allow for the egg to grow downward into the substrate. It is sometimes difficult to match nature and humidity levels that are optimum for each specie of snake. One year I had several Dry eggs that actually cut out of the bottom of the egg (totally unatural). I could see where they had tried to cut through the tough upper part of the shell. After that I started making sure the substrate maintained moisture and I monitored the toughness of the shell and even misted the tops of the shells occasionally.

Again, good job on your success. Sometimes all we can do is trial and error, especially when dealing with new species.

ECTimaeus