I've never had ball python eggs, but I have incubated corn snake, bull snake, and Burmese python eggs. IMO, Lord Sorril's answers are excellent.
I took Lord Sorril's "container" to mean the egg box. Then you do not need to seal the incubator. For what it's worth, I have always get an adequate seal by just putting the top on the egg box. I open the box once a week for air exchange (twice per week for relatively small egg boxes) until the last week or two. Then twice a week. Sometimes I have put an open box with the incubation medium inside a larger plastic box with a top that can be sealed. That may be possible if the incubator has enough vertical room. If the egg box is open, who knows what could suck up the humidity.
By the way, if the incubation boxes are the ones pictured in the original post and the egg crate squares are one inch square, then the boxes are only 6 inches by 9 inches. I've never used anything smaller than a shoe box (14x6x4 inches).
The 1:1 ratio of water to vermiculite only applies if the eggs are sitting on the vermiculite. If the eggs are on the egg crate, just saturate the vermiculite. By the way, many of the plastic shoe and sweater boxes that I've used had pinhole leaks in the corners. I've either plugged them with silicone or used a tray to catch any leaks.