Try this... send Europeans to Nigeria, slave them for a couple centuries, particularly the British, then amplify the infighting between the original nation-tribes to promote them selling each other into slavery, replace their language, religions, culture, then erase the boarders and bundle it into a single colony, use this slave labor for cash crops and minerals, then sign a treaty in Berlin with your european buddies like Norway to supercharge this exploitation and carve the continent into chunks. Then wait for the demise of the British empire, negotiate their independence in 1960 and see who is left with more resources and infrastructure.