Choppie. In a UH-1H that was well kitted out with composite blades, -703 engine etc, I was lifting a full water bucket out of a lake at 9200 feet and that was with about 800 pounds of fuel on board, enough for an hour at least. The bucket took 1300 litres which works out to over 2800 pounds.
I love the B3 but it is not going to come close either in lifting capacity or cost/pound when you consider the cost of acquisition of each helicopter. A really good UH-1H with all the goodies is going to cost you close to a million US while a B3 I seem to recall being well over 2 million US right now. For Africa, take the Huey. Wont be as easy to do survey with but there are other advantages which make it a good choice.