The snake is not in the wild it is in captivity, some of the rules change. That tank is way too big. Check out this thread for more info on cage size.
http://www.ssnakess.com/forums/showt...&threadid=8410
In my opinion, which I'm basing on things I've read and things that I know large breeders of ball do, I feel that balls should never be housed together. You mentioned that in the wild they have more then 130g of space, well in the wild they do not live together and that is one rule that transfers to captivity.
Here are some points that I keep in mind and reasons why I do not house them together.
1. The presence of another animal in their space represents competition, competition leads to stress.
2. Stress leads to loss of appetite and or disease.
3. If one sick gets sick they can both get sick.
4. How do you know who is defecating and who is not?
5. Snakes are not social animals so although captivity its self is not natural forcing two animals to live together is even more unnatural.
Cheers,
Trevor