Who have more Black African ancestry: Madeiran Portuguese, white Americans, or white South Africans?
Basically the question is, which white people are the blackest? :p
In my opinion:
Afrikaners > Madeirans > white US southerners
My mother's Madeiran cousins on 23andme all range from having 0.5 to 5% West African, and I have a DNA cousin on GEDmatch who scores 7%. But I also imagine Afrikaners can score as much, if not more.
I do not believe white US southerners to, as a whole, have Sub-Saharan African ancestry.