in lowpo's video, its hard to say if its quieter because "hammer isnt hitting anything" or if its quieter because when held in the air between fingers there's no resonance.
There are one or two clicks in the video where I let the hammer click freely against its end of movement point. That's also considerably louder than when the hammer is dampened by the finger.
But, having done some more tests, I think my hammer theory doesn't hold. Main reason: the click on the way up is a lot louder with the switch in the board than with the switch alone. And if I apply dampening then the ratio between the up and down sound is always the same: in the air (quiet), on the desk (not as quiet) and in the board (loud).
I'm with the combined sound folks now, I guess. Still, the hammer can provide a lot of noise depending on the situation (density of rubber mat, membrane thickness, travel).
The board adds A LOT of resonance, at least with the A01. There's probably little you can do about this.
Ripster, maybe you can remove the sloped part in one of your stems on your test setup?