It wasn't specified on his display when i got him, whereas other snakes had percentages, so i'm assuming that he is full mainland. Super dwarfs are awesome, the guy a my local shop has a pure SD snow, it's pretty damn magnificent. Are you planning on breeding? And do you have breeder pictures? I'd like to see them. As far as keeping the sizes manageable it seems like (and this is not personal experience of course but stuff ive seen on the forums and youtube) the only way to ensure they don't get massive is to have a high percentage sd, and even then it really comes down to the individual snakes feeding and genetics. I'm looking forward to having a big boy.