Are you serious? Known to not have a potent venom?
The first link that you posted states this about B.Nasicornis "VERY TOXIC BY INTRAVENOUS AND INTRAMUSCULAR ROUTES". Fortunately not much is known about Bitis N. or B. G. because not very many people have been bitten by them, due to their calm and lazy nature. They usually only bite when stepped on or harassed. Most of their data is from mice and monkeys.
Worlds most venomous snakes
To say that a Bitis N's venom is not potent is ignorant. Sure its not as potent as say a Taipan, but it is far from being non fatal. They are more fatal than many venomous snakes, such as the Agkistrodon contortrix, or Crotalus atrox which both have a low toxicity level. The B.N. is actually in the middle, but the amount of venom is indeed also a factor, as they do inject far more than any other snake.
"Bites are relatively rare, due to their docile nature and because their range is mainly limited to rainforest areas. Due to their sluggishness and unwillingness to move even when approached, people are often bitten after they accidentally step on them, but even then in some cases they may not bite. However, when a bite does occur, it should always be considered a serious medical emergency. Even an average bite from an average-sized specimen is potentially fatal. Antivenin should be administered as soon as possible to save the victim's life if not the affected limb."
A study by Marsh and Whaler was done and found that the equivalent to 0.06 ml of venom, or 1/50 to 1/1000 of what can be obtained in a single milking. 35 mg (1/30 of the average venom yield) would be enough to kill a man of 150lbs.
As far as pictures, I wish that we did still have pictures of our Rhino's. They were very beautiful. Unfortunately that was years and a few computers ago and we no longer have any of them.