Andrew,

You seem to have enough lead, but if you need a larger quantity I know
of a source of which most people are unaware. It is the nuclear
medicine department of your local hospital, usually a part of the
x-ray department. They get their radioactive medicine in lead "pigs"
that are cylinders about 4 inches in diameter and six inches high with
a rather small cavity in the middle. After they receive the medicine
they have to store the lead for a period of time (about 6 months as I
recall) and then they can dispose of them. Often nuclear medicine
techs have been known to sell the lead to recyclers for a little
supplement to their salaries. If you offer to take a friendly tech
sailing, you might be able to get some big chunks of lead for free or
a very cheap price.

Lee Huddleston