You should do this research before acquiring a snake.
But better late that never,
I'm Quoting out of Johan Marais' book , A Complete Guide to the snakes of Southern Africa:
The POTENTLY cytotoxic venom is comparable with that of the Puff Adder, but much larger quantities may be injected in a single bite. A full bite from a Gaboon Adder will result in alarming symptoms and early death unless the victim is treated promptly with antivenom. The victim must be treated for shock immedately. Symptoms may include sever pain, swelling and necrosis.
It's better that you asked than to not be sure, but nect time, be sure about everything before purchasing a snake.
Although you have some experience in keeping and handling venomous, this snake should be considered VERY dangerous.
Cheers
D