Oops, seems as if I am too late... but maybe it's interesting nevertheless: I use "String Tie"s (no additonal brandname) on my Rodríguez FF. I bought them to avoid scraching the bridge. You can turn the ugly graphic symbols also upside down. In that case, the parts will tilt a few degrees up from the top and resemble a microscopic "Floyd Rose Vibrato" (String bending doesn't work, no way
). The resin is caseine-based "Galalithe", soft surface, but firm. It works well, no scratches and there have never been problems with breaking strings or worn out holes in 2 1/2 years.
BTW: The impovement on sustain was acoustically marginal, but the higher pressure on the undersaddle piezo makes an audible difference!
I could imagine that a skilful tinkerer can cut/drill/polish a set for himself very easily in short time; maybe cocobolo, ebony, snakewood...
My main guitar (Hanika) doesn't need such things, because of a 12-hole-bridge.