You can easily create different weights of jig heads by simply changing the casting material. The jig heads from this mold come in the following weights depending on the the type of metals used:
22 grams (100% lead); 19 grams (50% lead + 50% tin); 15 gram (100% tin)
Pure tin is a great material for jig head making. It makes jig heads lighter, harder (abrasion resistant), it also gives them the shiny look shown in the pictures. You can quickly achieve that chrome look by using a nail file or fine sand paper.
*First handy tip: before pouring the metal, cover the mold surface with talcum powder. Blow away the redundant talcum.
*Second handy tip: in picture 2 and 3 you can see the coil of the wire screw is placed in a lighter pinkish area. This is plasticine/clay that you can add to fixate the coil and make it more stable while casting the lead. When removing the jig head, the clay comes off easily. Plasticine/clay is cheap and you would need just a gram or two of it.