3. Damping is exponential coefficient. You may need to adjust to your time scale.
Your signal is clean enough that this works well. I used the Peak Detector VI with the threshold set to .05 and the width to 5. The default width is 3 but you have a bit of noise so I widened the peak a bit to reduce the chances of "detecting" multiple peaks due to noise. Note that it does get multiples at 1439, 1442, 1444.
So that I do not need to read the file every time I run, I made the Waveform Graph value default and then converted it to a control.