As I have mentioned before, I am against housing snakes together. One other problem that can easily arise is that one of your snakes may stop eating. The problem at this point is that you may not be able to determine the cause because a real possibility is that the two snakes together is the problem. You can wait it out and see if your snake will eat again, but it may not and then you have waited 2 months for your snake to eat and still can't be sure why. Balls can be finicky eaters, and I just think the risk is not worth it imo. Too much stress for a new ball owner. you could always sell the tank and buy a couple tubs for your snakes. Or simply just have one snake to start.

Humidity can be a real problem in a glass tank setup. My brother went with a glass tank, and has found it extremely irritating to keep the humidity up. With a tub, it is super easy. Furthermore, balls really like the enclosed feel of tubs. Sure you cant really see your ball, but ball pythons sleep in their hides 95% of the time anyways. If you want to see them, just take them out for a visit.

Hope that helps a little, let us know what you decide and if you have any more questions