I have cast maybe 1500 lbs of lead so far this summer (10,12, and 15lbs cannonballs). I have jig head molds, Betty molds, slpit shot etc.
Bottom line is that over the past 5 years I have learned a lot from/about casting lead and really, for a small need like yours I can't see it being worth the time and effort. I mean, how many weights are you needing?
Scrap lead is available at a number of recycling yard thru out the GVRD. It is sold for roughly $1.00 a lb (and that buying 400lbs at a time)!!! last summer I was paying .55c, man I wish I bought a ton!
Anyhow melting a batch of lead with a propane torch is time consuming (I have used a torch before too) and you usually end up standing right over the pot...not the best plan. I now have an electric bottom pour pot for small stuff (under a lb) and a 60 lb pot that I use for my cannon balls. That is powered by a 200,000btu torch attached to a 20lb propane tank.
You may think it would be more economical to pour your own weights, but unless you are going thru a lot of lead and you have lots of time on your hands, then it can be a laborious project to start up.
If you have any questions feel free to email me.