I'm not sure if this is a good tip or not as I haven't made a wedge from fishing sinkers.
I got a roughly 18 inch long lead rod that is 3/4" in diameter delivered for $20. I then used my band saw to cut a bunch of little medallions very quickly. The lead rod is on Amazon. It's advertised as a foot, though mine was longer.
Thought I would share in case it is helpful.