Welcome aboard the Do-It forums.
Ned rigs have been a popular topic over the last year. The Do-It Midwest Finesse Jig head mold is a great place to get started. Lots of people use this head for Neds. Its an easy mold to cast and the heads finish beautifully with powder coat or a dipping paint like the CS Vinyl Lure Paint. Powder coat is the easiest to master and has no noticeable odor.
As for plastics, you could get the cnc style Senko molds or the Essential series molds, then just trim the baits to the length you want the Neds to be. The difference in baits from one mold to the other is nothing more than finish. The cnc molds produce a shiny finish on the bait while the Essential molds yield a bait that has a matte finish. In all honesty the two different bait finishes are a moot issue to the fish as the baits all look the same in the water. Both molds are very easy to inject and either is a great "starter" mold to learn from.
There are a lot of bass anglers here that do the Ned rigging and they'll likely chime in too. Again, though, welcome.