Nice find. Interesting video. Good idea using the steel shot. My only concern would be rust over time. Probably not critical but a concern. there are many dampening compounds to choose from. The key is reducingthe harmonics on the line. Alan Maher products come to mind in that regard. Where the shot reduces vibration the crystals [ Am] manage the harmonics.
curious ? has anyone tried attaching a CBF to each end of a stock cord and compared to a treated cord ? Might prove interesting.
charles