Drew, I have a Do-It mold to make Heddon Sonar clone blade baits. They use a brass or brass plated steel blade you place in the mold then pour melted lead to form the weighted body. The last special thing you need is a special form of treble hook that has a split shank. The finished product works splendidly.
Don’t get too worried about the evils of lead. I have smelted lead into thousands of cast bullets, hundreds of jigs, sinkers, and decoy anchors. Practice good hygiene and hand washing, don’t eat, drink, or smoke while casting. PM me for more lead melting and casting help if you need it. I’ve scrounged lead for 40 years. My stash probably shows up on a satellite image at the EPA. As anglers and hunters we don’t want to give up lead. We can be do it yourselfers with lead. Without it we are reduced to paying China for Tungsten.

Duke