Hi Thunder head,
I will try to help you judging this kind of buffalo.
First of all you have to pick up a bull in herd (from 15 to 100 heads). Often the bush is thick, so you have to be close enough, 50/60 yards, closer is better !!! The bulls are often on the side of the herd (on the wind side, so you can really see them) and at the back, protecting the herd. Female are smaller and thiner than the bulls. The front part of the body, shoulder and neck are not strong. The horns are thin, no boss but can be long. So double check.
You can train yourself with the following picture, tell me if you see any bull !!!
To judge a bull you have many criterias.
Look at the body signs: in a herd pick the biggest body and check the thickness of the neck, the roman nose and sometimes the dewlap. If there is many hairs on the penis it is also a good sign. All together you surely have a mature or an old bull.
When a buffalo is looking at you, the spread of the ears is about 27'', so you can appreciate the length of the horns. On the following picture n°2 the spread of the horns is about 25''.
The first thing you have to look if it is a shooter or not is the bases of the horns. If it is still white he is young with soft bosses.The gap between the horns is not a sign of age at all.
If the bases are hard and the horns smooth, you have a mature or old bull.
If the bases are hard, smooth horns and worn tips you have an old bull, over 12 years old. The best you can get.
Sure enough, you don't have 2 days to check all these criteras and the visibility is not perfect, so you have to trust your PH...
I hope it helps. Enjoy your trip in Burkina, for sure a great place to hunt.
Christophe