Seems that you just keep going and get enough single heads. My prompts are "sticky": if I change a prompt, it seems to keep the previous prompt for several photos, and then moves in the direction the prompt I asked it ... !
what I find best is to set steps to a low number like 20 or 30 then generate like 100 images with the same prompt but random seed. Delete the bad ones and keep the ones with the right general composition then use the seed from it and iterate on the prompt using a higher number of steps.
