The procedure was told by malta spero at the custom wooden gun tread but I remember some of the parts (or at least I would do them in this way

)
- choose th desired shape (blocks with the cross section of a wing)
- carve a piece of wood in the actual dive weight shape
- put some lime into a bucket, water it and put your model inside the model (side up).
- wait it to dry, than lift the wooden model.
- place an iron sheet with the same thickness width of your weight belt at the center of the curvature
- pour the molten lead
let it cool and dismantle it without breaking the mold....
I think the last part is the most difficult stage..
take care.