Well, the Integrity Toys Janay head, which I previously thought would be a good base for my 1:6 scale Bill Potts, ended up having an irredeemably sharp jaw, so I gave up on it. Thanks to @natalunasans, I am now in possession of a Fresh Doll Mia, who has a much better face shape. Below is a picture of Pearl Mackie at the DW season 10 photocall in London in April. Below that is a photo of Fresh Doll Mia after I braided some of the top left of her hair and then clipped back some of the top right. Looking good… Still needs redone eyes and lips. Also more eyeliner. Unsure about body, as this light brown/golden skintone is nowhere available in action figures.