Thanks
Dead soft will be tough to find. If you just want "softer than hard" that's much easier. Stick-on weights are not a true dead-soft lead, they are just softer than the hard-lead of the clip-ons. I have plenty of Stick On Weight (SOW) ingots but I keep them for cutting my Clip On Weight (COW) lead when I want a softer alloy.
I think stick-on weights are a preferred lead supply for that; they are a bit harder than dead-soft, but still soft enough to load by hand.I was wanting soft lead to make round balls for a percussion revolver. Though I have been reading that wheel weights can work OK as long as you use a loading press to load the cylinders. I tend to like to load that way anyway.