You must be excedingly careful using an old tank (I have been dying to get to use that icon for a real purpose).
So Dave, any chance we will see you play one of these at the IRI? I looked up the clips, and they sound amazing! Being a Noise and Vibration engineer, I am always amazed by the stuff figured out by raw experimentation. The guy calls out several great damping techniques as "Found this out, not sure why it works, but it works well..." I am always impressed with the ability and determination of tinkerers.