Harking back to my naval architecture days, I decided that I needed more than my meager stash of 5 lead ducks. However I wasn't very excited about making molds or melting lead, so I came up with the attached scheme for making some decent wood subsitutes.

Make template of center (red) section and cut out 1 1/2" thick pieces for as many ducks as desired. (note here that curved shape is handy to position a second duck upside down on back of primary duck to add more holding power to reluctant spline at a severe bend with a stiff spline.) Glue on (yellow) sides, and (blue) nose piece (cut sides to shape after gluing)

Turn up and fill with lead scraps if available (ie old wheel weights from tire shop or fishing weights or ?) then fill remaining with fairly fine lead shot to flush, and glue on bottom (green).

I used gorilla glue to help prevent lead shot covered floor in event of crash. The "grip-liner" is a big improvement over traditional felt lining, as friction is the ultimate goal here. Putting a fairly sharp end on the hook will help hold the spline in place, some splines are made with a shallow saw groove along the length for the hooks to grab. The ducks as dimensioned here will average approx three pounds.

happy trails
Ron