I have both rufous beaked and red-headed beaked snakes.
I would be very cautious of buying claimed CBB - only a handful of people have been able to successfully sex these animals let alone breed them. A person I consider probably to be the most experienced with this species has a heck of a time sexing them or getting them to even act like they want to breed.
Most are WC and come in with a parasite load.
A second thing to consider is that although they are rear-fanged and disinclined to bite, they are considered by many to be an improperly categorized elapid; and they also possess a neurotoxic venom comparable to other more lethal elapids.
There have been several papers written on the active neurotoxin in their venom - rufoxin. Biventer cervicis nerve tests on chicks have shown that the onset of symptom time and severity is comparable to front fanged elapids such as death adders and taipans. The only difference is that rhamphiophis have a heck of time envenomating humans.
In other words, effective venom but crappy delivery systems.