First, contrite_wheel thank you for developing this software. I basically scrapped my other timegrapher apps in favors of yours. I read the links you posted, and it looks like you ran into people with HUGE egos. So, thank you for your perseverance developing this software.
Instead of using a clip, I decided to go another route. Here is my setup - a notebook running your software, a box of electronics to provide adjustable gain and filtering, and a watch holder modified with a piezo speaker as a sensor.
Here is a picture of my amplifier box (with on/off switch and gain knob) and my modified watch holder.
Here is a zoom of my modified watch holder. The piezo speaker fits in between the holder's rails. I superglued a small plastic cylinder from a mechanical pencil to the speaker to act as a pickup. The plastic cylinder contacts the watch to pick up the movement's vibrations and won't scratch the watch.
Here is a picture with the piezo speaker moved to the side. I used an arch shaped piece of foam with a flat top inside to the holder to push the piezo speaker's pickup against the watch. The holder's spring and bolt fit inside the arch, and the top of the arch is flat to mate against the flat back of the piezo speaker.
This holder will allow you to balance the watch in 5 of the 6 measurement positions. When I need to take a measurement with the side of the holder with the bolt and wingnut, I'll set it against something or just hold the holder in that position. I'm working on a device that will let you rotate the holder in all 6 positions.
When I regulate my watches, I place the watch face down in the holder and open the back. I make the adjustments and see my changes on the timegrapher. For example, if your watch is running 20 s/d fast when you wear it and face down measures +15 s/d, you can adjust the face down s/d to be -5 s/d and this will get you close. For this example, I'd actually adjust face down to -4 s/d because I regulate my watches to run 0 to +1 s/d.
I made this setup well over a year ago, and I have to dig up my schematic for my amplifier. I think I had three or four filter/gain stages. The gain of the first stage is set internally by a potentiometer. The final gain is set by the knob on the outside. I used ultra low noise op amps. I didn't need 3 or 4 stages for the gain, but needed them to provide filtering from outside electrical and mechanical noise. I think I used a multi-pole band pass filter from ~500 Hz to 20kHz. This filtered out the 60 Hz and 120 Hz electrical noise and a lot of the room noise (talking, TV, etc.).
I used a quartz watch to perform the calibration as instructed. Then, (here comes the anal part), I checked the calibration of the quart watch over a long period of time and made a tweak to the initial calibration. This is a small ~0.2 s/d tweak to the initial calibration.
If there is a next version, is it possible to:
1) Select the integration time from several choices like the choices from a standalone timegrapher.
2) With a longer integration time, can you display the s/d with one number after the decimal point (e.g, +1.2 s/d).