Steve I think I just came up with a brilliant idea... another lester lightbulb moment for sure
Thinking about what you said you used for belly weight vs the original drawings, I got the idea that you could remove one weight...and in place of the missing weight throw a couple of bb's or stainless shot in there...click click tick tick click just like the noise that real bunker make..
You could even hollow out a larger cavity inside....use a rolling weight system like some of the plastic guys do...I like this 2 halves concept alot. Gives you alot of versatility.