Your challenge if you choose to accept it is to make Wicca a popular if not the dominant religion in sub-Saharan Africa anytime during the 20th century.
http://en.wikipedia.org/wiki/Wicca
http://en.wikipedia.org/wiki/Wicca
ASB essentially.
Religion in the modern world does'nt just spread, you have to have Missionaries or a colonial power enforcing the religion, which is why Sub-Saharan Africa is predominantly Christian (traditional and Syncretic).
Wicca developed long after that aspect of Colonialism was gone and Africa was in the middle of becoming independent and has never had the kind of support to allow it to propogate or the numbers for that matter.
You can have missionaries without a colonial power behind them. Hell, there are Evangelicals all over Latin America. Mormons in Europe, Muslims in America...
So, an sect of Wiccan, that adopts the idea of Missionaries...
Wicca is not an organized religion, it does'nt have sects, it's a series of related beliefs that are practiced individually or by small like-minded groups.
This. It's not an organized religion in any sense of the word, hell I don't even think there is a common doctrine of belief. You need a centralized structure with dedicated missionaries and most importantly money to spread major religions and Wiccan has neither :/