I have a SSHamburg hen. She's the smallest chicken in my flock ... about equal to my Silkies. I don't have OEGB so I can't compare those except for what I remember from seeing some at a friends house. The SSHamburg is twice the size of his OEGBs.
My ssh hen is tiny! She is smaller than all of my silkie's and about the same size as my OEBG hen, maybe a little bigger but just by an hair. She is the sweetest little girl ever. She talks, talks, talks when you hold her.