You can do all the above but it is much easier to just pester a machinist until he breaks down and makes you one to get you off his back. Just be persistent and don't take no for an answer.
If you have to do it yourself, drill the weight hole slightly undersized so you can slide the lead into the hole in your plug more easily.
You don't need stainless for the pull-rod. You can buy piano wire at the hardware store that works well. Buy something larger than the wire you use on your plugs (I think I bought .074) which makes it a lot easier to wire your plugs once assembled.