I chose to make 3', 3'4:, 3'8" and 4' pickets. I build 5 8' sections, and 2 4' section using 6 2x4's.
Then I cast finales and post caps, since 41 finales would cost a lot to buy. I used 1:1 mix of silicon caulk and cornstarch to build molds for some small skull heads, and larger ghoul head I had picked up over the years. Since I had so many to make, I cast the skull heads in plaster. When they were set, I drilled 3/8" hole in the bottom of each, and glued in a 2" piece of 3/8" dowel. Then I dipped the whole thing in polyurethane, then painted flat black finished with a dry brushing of metallic copper acrylics. The post toppers were cast in paper mache paste, and finished the same as the skulls.
The fence posts are built from 1 1/4" PVC. 3/8" dowels glued into the end of the rails are inserted into holes in the PVC posts. Some pictures of the finished fence sections are below.