The hologram would go over the black spot, because the black spot just represents an indention where you would put the private key.
So you have to stick the hologram on top of the face of the coin? It's off center and you'll cover the 'design' with the hologram. Also, why doesn't the design say '.999 silver' or something similar?
Judging by my rough calculations, I think the black spot is 8mm so if the hologram is positioned right, I do not think it will cover the B and if it does, only alittle amount.
The smallest the letters could be is 1mm and I couldn't find a good spot to put it.
edit: I could cut the holograms to fit if need be.
edit: I am also thinking about getting the holograms laser engraved to match the front serial number but that would increase the cost.