I know if you don't have enough air going into the incubator for chicken eggs they will all die of suffocation. I assume it's the same for snakes. All living things need to breathe. I actually put folded up paper towels on each end of the shoebox tubs under the lid to ensure there's enough air flow. And I monitor the humidity in my incubator, it stays at about 75%. The more air the better, just don't let them dry out too much. I also started using sphagnum moss in the tubs around the eggs, I soak the moss for a few seconds and squeeze it out before putting it in there, works great to keep the humidity up. Seems like everyone has a slightly different approach.
Also, I check on my eggs at least once a day. I was doing it twice a day but it seemed like opening the incubator that many times removed too much heat and humidity so I dropped back to just once a day. I check to make sure there's no condensation under the lid and it helps to get some fresh air in the incubator and in the boxes.