I got a factor of 3 or so reduction in motion (Figure 1) of a test stand blade spring with a captured mass on Viton pads that attaches to the end of the blade (Figure 2). I think that further development requires a better test stand with a loaded blade spring.  The damper is made of a 3” long, 1” square steel bar on adjustable Viton pads held inside a square aluminum tube with a 1.25” inner diameter. I think this should be reasonable to install (see photo of blade spring in place, Figure 3). In my setup I use a C-clamp to attach it to the blade spring in place of a small integrated clamp like the magnet-free blade clamps designed for SUS. I suspect that the Q is higher for the real setup than for my setup, so the improvement may be better in real life.