Redman-
You'll probably get better ideas from some of the more experienced individuals in the air sector (i.e. Merlin, Flitzer, etc.), But as an aviation researcher, here's my .002 USD.
The 'lead weights' you refer to are electrical isolators, placed on the long wave aerials to prevent static discharge from the airframe from interfering with the reception (or frying the components). Depending on the scale, these can usually be simulated with "blobs" of white glue. Another method is discs of sprue softened in liquid cement and pressed around the aerial. The originals were ceramic or bakelite, crimped onto the cables with soft lead or bronze. In a larger scale, come to think of it, small craft beads may be of use...
HTH