The 2/0 hook doesn't fit in the 1/8 oz. mold. The eye to bend is to long. Makes the hook ride on the barb side of the mold. You may get the barb, but no lead between the barb and head. If mold is super hot you'll get this area filled, but may have overfill as if mold isn't closed all the way. The swivel slot is made for a 14. It needs to be a bit longer for a 12.

Looking at the picture above. I'm guessing that is a 2/0 hook in the 1/4 slot. Look at the shank of the hook above the barb. It isn't center of the mold. It's to the right. Tighter fit in the 1/8 mold.