For good advice about antivenom, we recommend asking Johan Marais in South Africa and/or finding info from Global Snakebite Initiative. We are not expert on anti-venom, or up-to-date on specific manufacturers, but it is worth getting good advice from somebody who is, because there is a problem with ineffective anti-venom available for sale, marketed for use on African snakes. If you need a knowledgeable herpetologist in Congo, we highly recommend the Congolese grad student and former colleague of Kate Jackson from Harvard, Ange Zassi-Boulou in Brazzaville.
Because of the specific species that occur in the Congo and the fact that more than one antivenom may be required and in sufficient quantities, they would though not recommend that you actually purchase and keep stock unless you know what you are doing and have consulted an expert. We have seen individuals from US, Japan, and Europe bring the wrong antivenin and create a false sense of safety that would prevent them seeking real care in the event of a perilous snakebite.
Rather arrange insurance with the likes of specialists like ISOS or Inhemaco and in the unlikely event of a snakebite immediately medevac the patient to Johannesburg in South Africa. Mining clients from as far away as Senegal and Liberia evacuate all medical emergencies to Johannesburg. You do not want to spend time in a hospital in the Congo. The premiere expert group and guides are here below (they update continually editions):
